luci-base: luci.js: add LuCI.session.getToken()
[project/luci.git] / modules / luci-base / htdocs / luci-static / resources / luci.js
index 3a8c6b4b17b0dec6aa4584dec03ef552e84d14af..4b6894c080f1f1ed41fc74b3463d4af431f93209 100644 (file)
@@ -12,6 +12,8 @@
 (function(window, document, undefined) {
        'use strict';
 
+       var env = {};
+
        /* Object.assign polyfill for IE */
        if (typeof Object.assign !== 'function') {
                Object.defineProperty(Object, 'assign', {
        };
 
        /**
-        * @class Class
+        * @class baseclass
         * @hideconstructor
         * @memberof LuCI
         * @classdesc
         *
-        * `LuCI.Class` is the abstract base class all LuCI classes inherit from.
+        * `LuCI.baseclass` is the abstract base class all LuCI classes inherit from.
         *
         * It provides simple means to create subclasses of given classes and
         * implements prototypal inheritance.
                 * Extends this base class with the properties described in
                 * `properties` and returns a new subclassed Class instance
                 *
-                * @memberof LuCI.Class
+                * @memberof LuCI.baseclass
                 *
                 * @param {Object<string, *>} properties
                 * An object describing the properties to add to the new
                 * subclass.
                 *
-                * @returns {LuCI.Class}
-                * Returns a new LuCI.Class sublassed from this class, extended
+                * @returns {LuCI.baseclass}
+                * Returns a new LuCI.baseclass sublassed from this class, extended
                 * by the given properties and with its prototype set to this base
                 * class to enable inheritance. The resulting value represents a
                 * class constructor and can be instantiated with `new`.
                 * and returns the resulting subclassed Class instance.
                 *
                 * This function serves as a convenience shortcut for
-                * {@link LuCI.Class.extend Class.extend()} and subsequent
+                * {@link LuCI.baseclass.extend Class.extend()} and subsequent
                 * `new`.
                 *
-                * @memberof LuCI.Class
+                * @memberof LuCI.baseclass
                 *
                 * @param {Object<string, *>} properties
                 * An object describing the properties to add to the new
                 * Specifies arguments to be passed to the subclass constructor
                 * as-is in order to instantiate the new subclass.
                 *
-                * @returns {LuCI.Class}
-                * Returns a new LuCI.Class instance extended by the given
+                * @returns {LuCI.baseclass}
+                * Returns a new LuCI.baseclass instance extended by the given
                 * properties with its prototype set to this base class to
                 * enable inheritance.
                 */
                 * Calls the class constructor using `new` with the given argument
                 * array being passed as variadic parameters to the constructor.
                 *
-                * @memberof LuCI.Class
+                * @memberof LuCI.baseclass
                 *
                 * @param {Array<*>} params
                 * An array of arbitrary values which will be passed as arguments
                 * Specifies arguments to be passed to the subclass constructor
                 * as-is in order to instantiate the new subclass.
                 *
-                * @returns {LuCI.Class}
-                * Returns a new LuCI.Class instance extended by the given
+                * @returns {LuCI.baseclass}
+                * Returns a new LuCI.baseclass instance extended by the given
                 * properties with its prototype set to this base class to
                 * enable inheritance.
                 */
                /**
                 * Checks whether the given class value is a subclass of this class.
                 *
-                * @memberof LuCI.Class
+                * @memberof LuCI.baseclass
                 *
-                * @param {LuCI.Class} classValue
+                * @param {LuCI.baseclass} classValue
                 * The class object to test.
                 *
                 * @returns {boolean}
                         * `offset` and prepend any further given optional parameters to
                         * the beginning of the resulting array copy.
                         *
-                        * @memberof LuCI.Class
+                        * @memberof LuCI.baseclass
                         * @instance
                         *
                         * @param {Array<*>} args
                         *    Calls the `key()` method with parameters `arg1` and `arg2`
                         *    when found within one of the parent classes.
                         *
-                        * @memberof LuCI.Class
+                        * @memberof LuCI.baseclass
                         * @instance
                         *
                         * @param {string} key
 
 
        /**
-        * @class
+        * @class headers
         * @memberof LuCI
         * @hideconstructor
         * @classdesc
         * The `Headers` class is an internal utility class exposed in HTTP
         * response objects using the `response.headers` property.
         */
-       var Headers = Class.extend(/** @lends LuCI.Headers.prototype */ {
-               __name__: 'LuCI.XHR.Headers',
+       var Headers = Class.extend(/** @lends LuCI.headers.prototype */ {
+               __name__: 'LuCI.headers',
                __init__: function(xhr) {
                        var hdrs = this.headers = {};
                        xhr.getAllResponseHeaders().split(/\r\n/).forEach(function(line) {
                 * Note: Header-Names are case-insensitive.
                 *
                 * @instance
-                * @memberof LuCI.Headers
+                * @memberof LuCI.headers
                 * @param {string} name
                 * The header name to check
                 *
                 * Note: Header-Names are case-insensitive.
                 *
                 * @instance
-                * @memberof LuCI.Headers
+                * @memberof LuCI.headers
                 * @param {string} name
                 * The header name to read
                 *
        });
 
        /**
-        * @class
+        * @class response
         * @memberof LuCI
         * @hideconstructor
         * @classdesc
         * The `Response` class is an internal utility class representing HTTP responses.
         */
        var Response = Class.extend({
-               __name__: 'LuCI.XHR.Response',
+               __name__: 'LuCI.response',
                __init__: function(xhr, url, duration, headers, content) {
                        /**
                         * Describes whether the response is successful (status codes `200..299`) or not
                         * @instance
-                        * @memberof LuCI.Response
+                        * @memberof LuCI.response
                         * @name ok
                         * @type {boolean}
                         */
                        /**
                         * The numeric HTTP status code of the response
                         * @instance
-                        * @memberof LuCI.Response
+                        * @memberof LuCI.response
                         * @name status
                         * @type {number}
                         */
                        /**
                         * The HTTP status description message of the response
                         * @instance
-                        * @memberof LuCI.Response
+                        * @memberof LuCI.response
                         * @name statusText
                         * @type {string}
                         */
                        /**
                         * The HTTP headers of the response
                         * @instance
-                        * @memberof LuCI.Response
+                        * @memberof LuCI.response
                         * @name headers
-                        * @type {LuCI.Headers}
+                        * @type {LuCI.headers}
                         */
                        this.headers = (headers != null) ? headers : new Headers(xhr);
 
                        /**
                         * The total duration of the HTTP request in milliseconds
                         * @instance
-                        * @memberof LuCI.Response
+                        * @memberof LuCI.response
                         * @name duration
                         * @type {number}
                         */
                        /**
                         * The final URL of the request, i.e. after following redirects.
                         * @instance
-                        * @memberof LuCI.Response
+                        * @memberof LuCI.response
                         * @name url
                         * @type {string}
                         */
                        /* privates */
                        this.xhr = xhr;
 
-                       if (content != null && typeof(content) == 'object') {
+                       if (content instanceof Blob) {
+                               this.responseBlob = content;
+                               this.responseJSON = null;
+                               this.responseText = null;
+                       }
+                       else if (content != null && typeof(content) == 'object') {
+                               this.responseBlob = null;
                                this.responseJSON = content;
                                this.responseText = null;
                        }
                        else if (content != null) {
+                               this.responseBlob = null;
                                this.responseJSON = null;
                                this.responseText = String(content);
                        }
                        else {
                                this.responseJSON = null;
-                               this.responseText = xhr.responseText;
+
+                               if (xhr.responseType == 'blob') {
+                                       this.responseBlob = xhr.response;
+                                       this.responseText = null;
+                               }
+                               else {
+                                       this.responseBlob = null;
+                                       this.responseText = xhr.responseText;
+                               }
                        }
                },
 
                 * of the cloned instance.
                 *
                 * @instance
-                * @memberof LuCI.Response
+                * @memberof LuCI.response
                 * @param {*} [content]
                 * Override the content of the cloned response. Object values will be
                 * treated as JSON response data, all other types will be converted
                 * using `String()` and treated as response text.
                 *
-                * @returns {LuCI.Response}
+                * @returns {LuCI.response}
                 * The cloned `Response` instance.
                 */
                clone: function(content) {
                 * Access the response content as JSON data.
                 *
                 * @instance
-                * @memberof LuCI.Response
+                * @memberof LuCI.response
                 * @throws {SyntaxError}
                 * Throws `SyntaxError` if the content isn't valid JSON.
                 *
                 * Access the response content as string.
                 *
                 * @instance
-                * @memberof LuCI.Response
+                * @memberof LuCI.response
                 * @returns {string}
                 * The response content.
                 */
                                this.responseText = JSON.stringify(this.responseJSON);
 
                        return this.responseText;
+               },
+
+               /**
+                * Access the response content as blob.
+                *
+                * @instance
+                * @memberof LuCI.response
+                * @returns {Blob}
+                * The response content as blob.
+                */
+               blob: function() {
+                       return this.responseBlob;
                }
        });
 
        }
 
        /**
-        * @class
+        * @class request
         * @memberof LuCI
         * @hideconstructor
         * @classdesc
         * The `Request` class allows initiating HTTP requests and provides utilities
         * for dealing with responses.
         */
-       var Request = Class.singleton(/** @lends LuCI.Request.prototype */ {
-               __name__: 'LuCI.Request',
+       var Request = Class.singleton(/** @lends LuCI.request.prototype */ {
+               __name__: 'LuCI.request',
 
                interceptors: [],
 
                 * Turn the given relative URL into an absolute URL if necessary.
                 *
                 * @instance
-                * @memberof LuCI.Request
+                * @memberof LuCI.request
                 * @param {string} url
                 * The URL to convert.
                 *
 
                /**
                 * @typedef {Object} RequestOptions
-                * @memberof LuCI.Request
+                * @memberof LuCI.request
                 *
                 * @property {string} [method=GET]
                 * The HTTP method to use, e.g. `GET` or `POST`.
                 * @property {boolean} [credentials=false]
                 * Whether to include credentials such as cookies in the request.
                 *
+                * @property {string} [responseType=text]
+                * Overrides the request response type. Valid values or `text` to
+                * interpret the response as UTF-8 string or `blob` to handle the
+                * response as binary `Blob` data.
+                *
                 * @property {*} [content]
                 * Specifies the HTTP message body to send along with the request.
                 * If the value is a function, it is invoked and the return value
                 * Initiate an HTTP request to the given target.
                 *
                 * @instance
-                * @memberof LuCI.Request
+                * @memberof LuCI.request
                 * @param {string} target
                 * The URL to request.
                 *
-                * @param {LuCI.Request.RequestOptions} [options]
+                * @param {LuCI.request.RequestOptions} [options]
                 * Additional options to configure the request.
                 *
-                * @returns {Promise<LuCI.Response>}
+                * @returns {Promise<LuCI.response>}
                 * The resulting HTTP response.
                 */
                request: function(target, options) {
                                else
                                        opt.xhr.open(opt.method, opt.url, true);
 
-                               opt.xhr.responseType = 'text';
+                               opt.xhr.responseType = opt.responseType || 'text';
 
                                if ('overrideMimeType' in opt.xhr)
                                        opt.xhr.overrideMimeType('application/octet-stream');
                 * Initiate an HTTP GET request to the given target.
                 *
                 * @instance
-                * @memberof LuCI.Request
+                * @memberof LuCI.request
                 * @param {string} target
                 * The URL to request.
                 *
-                * @param {LuCI.Request.RequestOptions} [options]
+                * @param {LuCI.request.RequestOptions} [options]
                 * Additional options to configure the request.
                 *
-                * @returns {Promise<LuCI.Response>}
+                * @returns {Promise<LuCI.response>}
                 * The resulting HTTP response.
                 */
                get: function(url, options) {
                 * Initiate an HTTP POST request to the given target.
                 *
                 * @instance
-                * @memberof LuCI.Request
+                * @memberof LuCI.request
                 * @param {string} target
                 * The URL to request.
                 *
                 * @param {*} [data]
-                * The request data to send, see {@link LuCI.Request.RequestOptions} for details.
+                * The request data to send, see {@link LuCI.request.RequestOptions} for details.
                 *
-                * @param {LuCI.Request.RequestOptions} [options]
+                * @param {LuCI.request.RequestOptions} [options]
                 * Additional options to configure the request.
                 *
-                * @returns {Promise<LuCI.Response>}
+                * @returns {Promise<LuCI.response>}
                 * The resulting HTTP response.
                 */
                post: function(url, data, options) {
                /**
                 * Interceptor functions are invoked whenever an HTTP reply is received, in the order
                 * these functions have been registered.
-                * @callback LuCI.Request.interceptorFn
-                * @param {LuCI.Response} res
+                * @callback LuCI.request.interceptorFn
+                * @param {LuCI.response} res
                 * The HTTP response object
                 */
 
                 * implementing request retries before returning a failure.
                 *
                 * @instance
-                * @memberof LuCI.Request
-                * @param {LuCI.Request.interceptorFn} interceptorFn
+                * @memberof LuCI.request
+                * @param {LuCI.request.interceptorFn} interceptorFn
                 * The interceptor function to register.
                 *
-                * @returns {LuCI.Request.interceptorFn}
+                * @returns {LuCI.request.interceptorFn}
                 * The registered function.
                 */
                addInterceptor: function(interceptorFn) {
                 * function.
                 *
                 * @instance
-                * @memberof LuCI.Request
-                * @param {LuCI.Request.interceptorFn} interceptorFn
+                * @memberof LuCI.request
+                * @param {LuCI.request.interceptorFn} interceptorFn
                 * The interceptor function to remove.
                 *
                 * @returns {boolean}
 
                /**
                 * @class
-                * @memberof LuCI.Request
+                * @memberof LuCI.request
                 * @hideconstructor
                 * @classdesc
                 *
                 * The `Request.poll` class provides some convience wrappers around
-                * {@link LuCI.Poll} mainly to simplify registering repeating HTTP
+                * {@link LuCI.poll} mainly to simplify registering repeating HTTP
                 * request calls as polling functions.
                 */
                poll: {
                         * polled request is received or when the polled request timed
                         * out.
                         *
-                        * @callback LuCI.Request.poll~callbackFn
-                        * @param {LuCI.Response} res
+                        * @callback LuCI.request.poll~callbackFn
+                        * @param {LuCI.response} res
                         * The HTTP response object.
                         *
                         * @param {*} data
                         * to invoke whenever a response for the request is received.
                         *
                         * @instance
-                        * @memberof LuCI.Request.poll
+                        * @memberof LuCI.request.poll
                         * @param {number} interval
                         * The poll interval in seconds.
                         *
                         * @param {string} url
                         * The URL to request on each poll.
                         *
-                        * @param {LuCI.Request.RequestOptions} [options]
+                        * @param {LuCI.request.RequestOptions} [options]
                         * Additional options to configure the request.
                         *
-                        * @param {LuCI.Request.poll~callbackFn} [callback]
-                        * {@link LuCI.Request.poll~callbackFn Callback} function to
+                        * @param {LuCI.request.poll~callbackFn} [callback]
+                        * {@link LuCI.request.poll~callbackFn Callback} function to
                         * invoke for each HTTP reply.
                         *
                         * @throws {TypeError}
                        /**
                         * Remove a polling request that has been previously added using `add()`.
                         * This function is essentially a wrapper around
-                        * {@link LuCI.Poll.remove LuCI.Poll.remove()}.
+                        * {@link LuCI.poll.remove LuCI.poll.remove()}.
                         *
                         * @instance
-                        * @memberof LuCI.Request.poll
+                        * @memberof LuCI.request.poll
                         * @param {function} entry
-                        * The poll function returned by {@link LuCI.Request.poll#add add()}.
+                        * The poll function returned by {@link LuCI.request.poll#add add()}.
                         *
                         * @returns {boolean}
                         * Returns `true` if any function has been removed, else `false`.
                        remove: function(entry) { return Poll.remove(entry) },
 
                        /**
-                         * Alias for {@link LuCI.Poll.start LuCI.Poll.start()}.
+                         * Alias for {@link LuCI.poll.start LuCI.poll.start()}.
                          *
                          * @instance
-                         * @memberof LuCI.Request.poll
+                         * @memberof LuCI.request.poll
                          */
                        start: function() { return Poll.start() },
 
                        /**
-                         * Alias for {@link LuCI.Poll.stop LuCI.Poll.stop()}.
+                         * Alias for {@link LuCI.poll.stop LuCI.poll.stop()}.
                          *
                          * @instance
-                         * @memberof LuCI.Request.poll
+                         * @memberof LuCI.request.poll
                          */
                        stop: function() { return Poll.stop() },
 
                        /**
-                         * Alias for {@link LuCI.Poll.active LuCI.Poll.active()}.
+                         * Alias for {@link LuCI.poll.active LuCI.poll.active()}.
                          *
                          * @instance
-                         * @memberof LuCI.Request.poll
+                         * @memberof LuCI.request.poll
                          */
                        active: function() { return Poll.active() }
                }
        });
 
        /**
-        * @class
+        * @class poll
         * @memberof LuCI
         * @hideconstructor
         * @classdesc
         * as well as starting, stopping and querying the state of the polling
         * loop.
         */
-       var Poll = Class.singleton(/** @lends LuCI.Poll.prototype */ {
-               __name__: 'LuCI.Poll',
+       var Poll = Class.singleton(/** @lends LuCI.poll.prototype */ {
+               __name__: 'LuCI.poll',
 
                queue: [],
 
                 * already started at this point, it will be implicitely started.
                 *
                 * @instance
-                * @memberof LuCI.Poll
+                * @memberof LuCI.poll
                 * @param {function} fn
                 * The function to invoke on each poll interval.
                 *
                 */
                add: function(fn, interval) {
                        if (interval == null || interval <= 0)
-                               interval = window.L ? window.L.env.pollinterval : null;
+                               interval = env.pollinterval || null;
 
                        if (isNaN(interval) || typeof(fn) != 'function')
-                               throw new TypeError('Invalid argument to LuCI.Poll.add()');
+                               throw new TypeError('Invalid argument to LuCI.poll.add()');
 
                        for (var i = 0; i < this.queue.length; i++)
                                if (this.queue[i].fn === fn)
                 * are registered, the polling loop is implicitely stopped.
                 *
                 * @instance
-                * @memberof LuCI.Poll
+                * @memberof LuCI.poll
                 * @param {function} fn
                 * The function to remove.
                 *
                 */
                remove: function(fn) {
                        if (typeof(fn) != 'function')
-                               throw new TypeError('Invalid argument to LuCI.Poll.remove()');
+                               throw new TypeError('Invalid argument to LuCI.poll.remove()');
 
                        var len = this.queue.length;
 
                 * to the `document` object upon successful start.
                 *
                 * @instance
-                * @memberof LuCI.Poll
+                * @memberof LuCI.poll
                 * @returns {boolean}
                 * Returns `true` if polling has been started (or if no functions
                 * where registered) or `false` when the polling loop already runs.
                 * to the `document` object upon successful stop.
                 *
                 * @instance
-                * @memberof LuCI.Poll
+                * @memberof LuCI.poll
                 * @returns {boolean}
                 * Returns `true` if polling has been stopped or `false` if it din't
                 * run to begin with.
                 * Test whether the polling loop is running.
                 *
                 * @instance
-                * @memberof LuCI.Poll
+                * @memberof LuCI.poll
                 * @returns {boolean} - Returns `true` if polling is active, else `false`.
                 */
                active: function() {
                }
        });
 
+       /**
+        * @class dom
+        * @memberof LuCI
+        * @hideconstructor
+        * @classdesc
+        *
+        * The `dom` class provides convenience method for creating and
+        * manipulating DOM elements.
+        *
+        * To import the class in views, use `'require dom'`, to import it in
+        * external JavaScript, use `L.require("dom").then(...)`.
+        */
+       var DOM = Class.singleton(/** @lends LuCI.dom.prototype */ {
+               __name__: 'LuCI.dom',
 
-       var dummyElem = null,
-           domParser = null,
-           originalCBIInit = null,
-           rpcBaseURL = null,
-           sysFeatures = null,
-           classes = {};
+               /**
+                * Tests whether the given argument is a valid DOM `Node`.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {*} e
+                * The value to test.
+                *
+                * @returns {boolean}
+                * Returns `true` if the value is a DOM `Node`, else `false`.
+                */
+               elem: function(e) {
+                       return (e != null && typeof(e) == 'object' && 'nodeType' in e);
+               },
 
-       var LuCI = Class.extend(/** @lends LuCI.prototype */ {
-               __name__: 'LuCI',
-               __init__: function(env) {
+               /**
+                * Parses a given string as HTML and returns the first child node.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {string} s
+                * A string containing an HTML fragment to parse. Note that only
+                * the first result of the resulting structure is returned, so an
+                * input value of `<div>foo</div> <div>bar</div>` will only return
+                * the first `div` element node.
+                *
+                * @returns {Node}
+                * Returns the first DOM `Node` extracted from the HTML fragment or
+                * `null` on parsing failures or if no element could be found.
+                */
+               parse: function(s) {
+                       var elem;
 
-                       document.querySelectorAll('script[src*="/luci.js"]').forEach(function(s) {
-                               if (env.base_url == null || env.base_url == '') {
-                                       var m = (s.getAttribute('src') || '').match(/^(.*)\/luci\.js(?:\?v=([^?]+))?$/);
-                                       if (m) {
-                                               env.base_url = m[1];
-                                               env.resource_version = m[2];
-                                       }
+                       try {
+                               domParser = domParser || new DOMParser();
+                               elem = domParser.parseFromString(s, 'text/html').body.firstChild;
+                       }
+                       catch(e) {}
+
+                       if (!elem) {
+                               try {
+                                       dummyElem = dummyElem || document.createElement('div');
+                                       dummyElem.innerHTML = s;
+                                       elem = dummyElem.firstChild;
                                }
-                       });
+                               catch (e) {}
+                       }
 
-                       if (env.base_url == null)
-                               this.error('InternalError', 'Cannot find url of luci.js');
+                       return elem || null;
+               },
+
+               /**
+                * Tests whether a given `Node` matches the given query selector.
+                *
+                * This function is a convenience wrapper around the standard
+                * `Node.matches("selector")` function with the added benefit that
+                * the `node` argument may be a non-`Node` value, in which case
+                * this function simply returns `false`.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {*} node
+                * The `Node` argument to test the selector against.
+                *
+                * @param {string} [selector]
+                * The query selector expression to test against the given node.
+                *
+                * @returns {boolean}
+                * Returns `true` if the given node matches the specified selector
+                * or `false` when the node argument is no valid DOM `Node` or the
+                * selector didn't match.
+                */
+               matches: function(node, selector) {
+                       var m = this.elem(node) ? node.matches || node.msMatchesSelector : null;
+                       return m ? m.call(node, selector) : false;
+               },
 
-                       env.cgi_base = env.scriptname.replace(/\/[^\/]+$/, '');
+               /**
+                * Returns the closest parent node that matches the given query
+                * selector expression.
+                *
+                * This function is a convenience wrapper around the standard
+                * `Node.closest("selector")` function with the added benefit that
+                * the `node` argument may be a non-`Node` value, in which case
+                * this function simply returns `null`.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {*} node
+                * The `Node` argument to find the closest parent for.
+                *
+                * @param {string} [selector]
+                * The query selector expression to test against each parent.
+                *
+                * @returns {Node|null}
+                * Returns the closest parent node matching the selector or
+                * `null` when the node argument is no valid DOM `Node` or the
+                * selector didn't match any parent.
+                */
+               parent: function(node, selector) {
+                       if (this.elem(node) && node.closest)
+                               return node.closest(selector);
 
-                       Object.assign(this.env, env);
+                       while (this.elem(node))
+                               if (this.matches(node, selector))
+                                       return node;
+                               else
+                                       node = node.parentNode;
 
-                       document.addEventListener('poll-start', function(ev) {
-                               document.querySelectorAll('[id^="xhr_poll_status"]').forEach(function(e) {
-                                       e.style.display = (e.id == 'xhr_poll_status_off') ? 'none' : '';
-                               });
-                       });
+                       return null;
+               },
 
-                       document.addEventListener('poll-stop', function(ev) {
-                               document.querySelectorAll('[id^="xhr_poll_status"]').forEach(function(e) {
-                                       e.style.display = (e.id == 'xhr_poll_status_on') ? 'none' : '';
-                               });
-                       });
+               /**
+                * Appends the given children data to the given node.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {*} node
+                * The `Node` argument to append the children to.
+                *
+                * @param {*} [children]
+                * The childrens to append to the given node.
+                *
+                * When `children` is an array, then each item of the array
+                * will be either appended as child element or text node,
+                * depending on whether the item is a DOM `Node` instance or
+                * some other non-`null` value. Non-`Node`, non-`null` values
+                * will be converted to strings first before being passed as
+                * argument to `createTextNode()`.
+                *
+                * When `children` is a function, it will be invoked with
+                * the passed `node` argument as sole parameter and the `append`
+                * function will be invoked again, with the given `node` argument
+                * as first and the return value of the `children` function as
+                * second parameter.
+                *
+                * When `children` is is a DOM `Node` instance, it will be
+                * appended to the given `node`.
+                *
+                * When `children` is any other non-`null` value, it will be
+                * converted to a string and appened to the `innerHTML` property
+                * of the given `node`.
+                *
+                * @returns {Node|null}
+                * Returns the last children `Node` appended to the node or `null`
+                * if either the `node` argument was no valid DOM `node` or if the
+                * `children` was `null` or didn't result in further DOM nodes.
+                */
+               append: function(node, children) {
+                       if (!this.elem(node))
+                               return null;
 
-                       var domReady = new Promise(function(resolveFn, rejectFn) {
-                               document.addEventListener('DOMContentLoaded', resolveFn);
-                       });
+                       if (Array.isArray(children)) {
+                               for (var i = 0; i < children.length; i++)
+                                       if (this.elem(children[i]))
+                                               node.appendChild(children[i]);
+                                       else if (children !== null && children !== undefined)
+                                               node.appendChild(document.createTextNode('' + children[i]));
 
-                       Promise.all([
-                               domReady,
-                               this.require('ui'),
-                               this.require('rpc'),
-                               this.require('form'),
-                               this.probeRPCBaseURL()
-                       ]).then(this.setupDOM.bind(this)).catch(this.error);
+                               return node.lastChild;
+                       }
+                       else if (typeof(children) === 'function') {
+                               return this.append(node, children(node));
+                       }
+                       else if (this.elem(children)) {
+                               return node.appendChild(children);
+                       }
+                       else if (children !== null && children !== undefined) {
+                               node.innerHTML = '' + children;
+                               return node.lastChild;
+                       }
 
-                       originalCBIInit = window.cbi_init;
-                       window.cbi_init = function() {};
+                       return null;
                },
 
                /**
-                * Captures the current stack trace and throws an error of the
-                * specified type as a new exception. Also logs the exception as
-                * error to the debug console if it is available.
+                * Replaces the content of the given node with the given children.
+                *
+                * This function first removes any children of the given DOM
+                * `Node` and then adds the given given children following the
+                * rules outlined below.
                 *
                 * @instance
-                * @memberof LuCI
+                * @memberof LuCI.dom
+                * @param {*} node
+                * The `Node` argument to replace the children of.
+                *
+                * @param {*} [children]
+                * The childrens to replace into the given node.
+                *
+                * When `children` is an array, then each item of the array
+                * will be either appended as child element or text node,
+                * depending on whether the item is a DOM `Node` instance or
+                * some other non-`null` value. Non-`Node`, non-`null` values
+                * will be converted to strings first before being passed as
+                * argument to `createTextNode()`.
+                *
+                * When `children` is a function, it will be invoked with
+                * the passed `node` argument as sole parameter and the `append`
+                * function will be invoked again, with the given `node` argument
+                * as first and the return value of the `children` function as
+                * second parameter.
+                *
+                * When `children` is is a DOM `Node` instance, it will be
+                * appended to the given `node`.
+                *
+                * When `children` is any other non-`null` value, it will be
+                * converted to a string and appened to the `innerHTML` property
+                * of the given `node`.
+                *
+                * @returns {Node|null}
+                * Returns the last children `Node` appended to the node or `null`
+                * if either the `node` argument was no valid DOM `node` or if the
+                * `children` was `null` or didn't result in further DOM nodes.
+                */
+               content: function(node, children) {
+                       if (!this.elem(node))
+                               return null;
+
+                       var dataNodes = node.querySelectorAll('[data-idref]');
+
+                       for (var i = 0; i < dataNodes.length; i++)
+                               delete this.registry[dataNodes[i].getAttribute('data-idref')];
+
+                       while (node.firstChild)
+                               node.removeChild(node.firstChild);
+
+                       return this.append(node, children);
+               },
+
+               /**
+                * Sets attributes or registers event listeners on element nodes.
                 *
-                * @param {Error|string} [type=Error]
-                * Either a string specifying the type of the error to throw or an
-                * existing `Error` instance to copy.
+                * @instance
+                * @memberof LuCI.dom
+                * @param {*} node
+                * The `Node` argument to set the attributes or add the event
+                * listeners for. When the given `node` value is not a valid
+                * DOM `Node`, the function returns and does nothing.
+                *
+                * @param {string|Object<string, *>} key
+                * Specifies either the attribute or event handler name to use,
+                * or an object containing multiple key, value pairs which are
+                * each added to the node as either attribute or event handler,
+                * depending on the respective value.
                 *
-                * @param {string} [fmt=Unspecified error]
-                * A format string which is used to form the error message, together
-                * with all subsequent optional arguments.
+                * @param {*} [val]
+                * Specifies the attribute value or event handler function to add.
+                * If the `key` parameter is an `Object`, this parameter will be
+                * ignored.
                 *
-                * @param {...*} [args]
-                * Zero or more variable arguments to the supplied format string.
+                * When `val` is of type function, it will be registered as event
+                * handler on the given `node` with the `key` parameter being the
+                * event name.
                 *
-                * @throws {Error}
-                * Throws the created error object with the captured stack trace
-                * appended to the message and the type set to the given type
-                * argument or copied from the given error instance.
+                * When `val` is of type object, it will be serialized as JSON and
+                * added as attribute to the given `node`, using the given `key`
+                * as attribute name.
+                *
+                * When `val` is of any other type, it will be added as attribute
+                * to the given `node` as-is, with the underlying `setAttribute()`
+                * call implicitely turning it into a string.
                 */
-               raise: function(type, fmt /*, ...*/) {
-                       var e = null,
-                           msg = fmt ? String.prototype.format.apply(fmt, this.varargs(arguments, 2)) : null,
-                           stack = null;
+               attr: function(node, key, val) {
+                       if (!this.elem(node))
+                               return null;
 
-                       if (type instanceof Error) {
-                               e = type;
+                       var attr = null;
 
-                               if (msg)
-                                       e.message = msg + ': ' + e.message;
-                       }
-                       else {
-                               try { throw new Error('stacktrace') }
-                               catch (e2) { stack = (e2.stack || '').split(/\n/) }
+                       if (typeof(key) === 'object' && key !== null)
+                               attr = key;
+                       else if (typeof(key) === 'string')
+                               attr = {}, attr[key] = val;
 
-                               e = new (window[type || 'Error'] || Error)(msg || 'Unspecified error');
-                               e.name = type || 'Error';
-                       }
+                       for (key in attr) {
+                               if (!attr.hasOwnProperty(key) || attr[key] == null)
+                                       continue;
 
-                       stack = (stack || []).map(function(frame) {
-                               frame = frame.replace(/(.*?)@(.+):(\d+):(\d+)/g, 'at $1 ($2:$3:$4)').trim();
-                               return frame ? '  ' + frame : '';
-                       });
+                               switch (typeof(attr[key])) {
+                               case 'function':
+                                       node.addEventListener(key, attr[key]);
+                                       break;
 
-                       if (!/^  at /.test(stack[0]))
-                               stack.shift();
+                               case 'object':
+                                       node.setAttribute(key, JSON.stringify(attr[key]));
+                                       break;
 
-                       if (/\braise /.test(stack[0]))
-                               stack.shift();
+                               default:
+                                       node.setAttribute(key, attr[key]);
+                               }
+                       }
+               },
 
-                       if (/\berror /.test(stack[0]))
-                               stack.shift();
+               /**
+                * Creates a new DOM `Node` from the given `html`, `attr` and
+                * `data` parameters.
+                *
+                * This function has multiple signatures, it can be either invoked
+                * in the form `create(html[, attr[, data]])` or in the form
+                * `create(html[, data])`. The used variant is determined from the
+                * type of the second argument.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {*} html
+                * Describes the node to create.
+                *
+                * When the value of `html` is of type array, a `DocumentFragment`
+                * node is created and each item of the array is first converted
+                * to a DOM `Node` by passing it through `create()` and then added
+                * as child to the fragment.
+                *
+                * When the value of `html` is a DOM `Node` instance, no new
+                * element will be created but the node will be used as-is.
+                *
+                * When the value of `html` is a string starting with `<`, it will
+                * be passed to `dom.parse()` and the resulting value is used.
+                *
+                * When the value of `html` is any other string, it will be passed
+                * to `document.createElement()` for creating a new DOM `Node` of
+                * the given name.
+                *
+                * @param {Object<string, *>} [attr]
+                * Specifies an Object of key, value pairs to set as attributes
+                * or event handlers on the created node. Refer to
+                * {@link LuCI.dom#attr dom.attr()} for details.
+                *
+                * @param {*} [data]
+                * Specifies children to append to the newly created element.
+                * Refer to {@link LuCI.dom#append dom.append()} for details.
+                *
+                * @throws {InvalidCharacterError}
+                * Throws an `InvalidCharacterError` when the given `html`
+                * argument contained malformed markup (such as not escaped
+                * `&` characters in XHTML mode) or when the given node name
+                * in `html` contains characters which are not legal in DOM
+                * element names, such as spaces.
+                *
+                * @returns {Node}
+                * Returns the newly created `Node`.
+                */
+               create: function() {
+                       var html = arguments[0],
+                           attr = arguments[1],
+                           data = arguments[2],
+                           elem;
+
+                       if (!(attr instanceof Object) || Array.isArray(attr))
+                               data = attr, attr = null;
+
+                       if (Array.isArray(html)) {
+                               elem = document.createDocumentFragment();
+                               for (var i = 0; i < html.length; i++)
+                                       elem.appendChild(this.create(html[i]));
+                       }
+                       else if (this.elem(html)) {
+                               elem = html;
+                       }
+                       else if (html.charCodeAt(0) === 60) {
+                               elem = this.parse(html);
+                       }
+                       else {
+                               elem = document.createElement(html);
+                       }
 
-                       if (stack.length)
-                               e.message += '\n' + stack.join('\n');
+                       if (!elem)
+                               return null;
 
-                       if (window.console && console.debug)
-                               console.debug(e);
+                       this.attr(elem, attr);
+                       this.append(elem, data);
 
-                       throw e;
+                       return elem;
                },
 
+               registry: {},
+
                /**
-                * A wrapper around {@link LuCI#raise raise()} which also renders
-                * the error either as modal overlay when `ui.js` is already loaed
-                * or directly into the view body.
+                * Attaches or detaches arbitrary data to and from a DOM `Node`.
+                *
+                * This function is useful to attach non-string values or runtime
+                * data that is not serializable to DOM nodes. To decouple data
+                * from the DOM, values are not added directly to nodes, but
+                * inserted into a registry instead which is then referenced by a
+                * string key stored as `data-idref` attribute in the node.
+                *
+                * This function has multiple signatures and is sensitive to the
+                * number of arguments passed to it.
+                *
+                *  - `dom.data(node)` -
+                *     Fetches all data associated with the given node.
+                *  - `dom.data(node, key)` -
+                *     Fetches a specific key associated with the given node.
+                *  - `dom.data(node, key, val)` -
+                *     Sets a specific key to the given value associated with the
+                *     given node.
+                *  - `dom.data(node, null)` -
+                *     Clears any data associated with the node.
+                *  - `dom.data(node, key, null)` -
+                *     Clears the given key associated with the node.
                 *
                 * @instance
-                * @memberof LuCI
-                *
-                * @param {Error|string} [type=Error]
-                * Either a string specifying the type of the error to throw or an
-                * existing `Error` instance to copy.
+                * @memberof LuCI.dom
+                * @param {Node} node
+                * The DOM `Node` instance to set or retrieve the data for.
                 *
-                * @param {string} [fmt=Unspecified error]
-                * A format string which is used to form the error message, together
-                * with all subsequent optional arguments.
+                * @param {string|null} [key]
+                * This is either a string specifying the key to retrieve, or
+                * `null` to unset the entire node data.
                 *
-                * @param {...*} [args]
-                * Zero or more variable arguments to the supplied format string.
+                * @param {*|null} [val]
+                * This is either a non-`null` value to set for a given key or
+                * `null` to remove the given `key` from the specified node.
                 *
-                * @throws {Error}
-                * Throws the created error object with the captured stack trace
-                * appended to the message and the type set to the given type
-                * argument or copied from the given error instance.
+                * @returns {*}
+                * Returns the get or set value, or `null` when no value could
+                * be found.
                 */
-               error: function(type, fmt /*, ...*/) {
-                       try {
-                               L.raise.apply(L, Array.prototype.slice.call(arguments));
+               data: function(node, key, val) {
+                       if (!node || !node.getAttribute)
+                               return null;
+
+                       var id = node.getAttribute('data-idref');
+
+                       /* clear all data */
+                       if (arguments.length > 1 && key == null) {
+                               if (id != null) {
+                                       node.removeAttribute('data-idref');
+                                       val = this.registry[id]
+                                       delete this.registry[id];
+                                       return val;
+                               }
+
+                               return null;
                        }
-                       catch (e) {
-                               if (!e.reported) {
-                                       if (L.ui)
-                                               L.ui.addNotification(e.name || _('Runtime error'),
-                                                       E('pre', {}, e.message), 'danger');
-                                       else
-                                               L.dom.content(document.querySelector('#maincontent'),
-                                                       E('pre', { 'class': 'alert-message error' }, e.message));
 
-                                       e.reported = true;
+                       /* clear a key */
+                       else if (arguments.length > 2 && key != null && val == null) {
+                               if (id != null) {
+                                       val = this.registry[id][key];
+                                       delete this.registry[id][key];
+                                       return val;
                                }
 
-                               throw e;
+                               return null;
+                       }
+
+                       /* set a key */
+                       else if (arguments.length > 2 && key != null && val != null) {
+                               if (id == null) {
+                                       do { id = Math.floor(Math.random() * 0xffffffff).toString(16) }
+                                       while (this.registry.hasOwnProperty(id));
+
+                                       node.setAttribute('data-idref', id);
+                                       this.registry[id] = {};
+                               }
+
+                               return (this.registry[id][key] = val);
                        }
+
+                       /* get all data */
+                       else if (arguments.length == 1) {
+                               if (id != null)
+                                       return this.registry[id];
+
+                               return null;
+                       }
+
+                       /* get a key */
+                       else if (arguments.length == 2) {
+                               if (id != null)
+                                       return this.registry[id][key];
+                       }
+
+                       return null;
                },
 
                /**
-                * Return a bound function using the given `self` as `this` context
-                * and any further arguments as parameters to the bound function.
+                * Binds the given class instance ot the specified DOM `Node`.
                 *
-                * @instance
-                * @memberof LuCI
+                * This function uses the `dom.data()` facility to attach the
+                * passed instance of a Class to a node. This is needed for
+                * complex widget elements or similar where the corresponding
+                * class instance responsible for the element must be retrieved
+                * from DOM nodes obtained by `querySelector()` or similar means.
                 *
-                * @param {function} fn
-                * The function to bind.
+                * @instance
+                * @memberof LuCI.dom
+                * @param {Node} node
+                * The DOM `Node` instance to bind the class to.
                 *
-                * @param {*} self
-                * The value to bind as `this` context to the specified function.
+                * @param {Class} inst
+                * The Class instance to bind to the node.
                 *
-                * @param {...*} [args]
-                * Zero or more variable arguments which are bound to the function
-                * as parameters.
+                * @throws {TypeError}
+                * Throws a `TypeError` when the given instance argument isn't
+                * a valid Class instance.
                 *
-                * @returns {function}
-                * Returns the bound function.
+                * @returns {Class}
+                * Returns the bound class instance.
                 */
-               bind: function(fn, self /*, ... */) {
-                       return Function.prototype.bind.apply(fn, this.varargs(arguments, 2, self));
+               bindClassInstance: function(node, inst) {
+                       if (!(inst instanceof Class))
+                               LuCI.prototype.error('TypeError', 'Argument must be a class instance');
+
+                       return this.data(node, '_class', inst);
                },
 
                /**
-                * Load an additional LuCI JavaScript class and its dependencies,
-                * instantiate it and return the resulting class instance. Each
-                * class is only loaded once. Subsequent attempts to load the same
-                * class will return the already instantiated class.
+                * Finds a bound class instance on the given node itself or the
+                * first bound instance on its closest parent node.
                 *
                 * @instance
-                * @memberof LuCI
+                * @memberof LuCI.dom
+                * @param {Node} node
+                * The DOM `Node` instance to start from.
                 *
-                * @param {string} name
-                * The name of the class to load in dotted notation. Dots will
-                * be replaced by spaces and joined with the runtime-determined
-                * base URL of LuCI.js to form an absolute URL to load the class
-                * file from.
-                *
-                * @throws {DependencyError}
-                * Throws a `DependencyError` when the class to load includes
-                * circular dependencies.
+                * @returns {Class|null}
+                * Returns the founds class instance if any or `null` if no bound
+                * class could be found on the node itself or any of its parents.
+                */
+               findClassInstance: function(node) {
+                       var inst = null;
+
+                       do {
+                               inst = this.data(node, '_class');
+                               node = node.parentNode;
+                       }
+                       while (!(inst instanceof Class) && node != null);
+
+                       return inst;
+               },
+
+               /**
+                * Finds a bound class instance on the given node itself or the
+                * first bound instance on its closest parent node and invokes
+                * the specified method name on the found class instance.
                 *
-                * @throws {NetworkError}
-                * Throws `NetworkError` when the underlying {@link LuCI.Request}
-                * call failed.
+                * @instance
+                * @memberof LuCI.dom
+                * @param {Node} node
+                * The DOM `Node` instance to start from.
                 *
-                * @throws {SyntaxError}
-                * Throws `SyntaxError` when the loaded class file code cannot
-                * be interpreted by `eval`.
+                * @param {string} method
+                * The name of the method to invoke on the found class instance.
                 *
-                * @throws {TypeError}
-                * Throws `TypeError` when the class file could be loaded and
-                * interpreted, but when invoking its code did not yield a valid
-                * class instance.
+                * @param {...*} params
+                * Additional arguments to pass to the invoked method as-is.
                 *
-                * @returns {Promise<LuCI#Class>}
-                * Returns the instantiated class.
+                * @returns {*|null}
+                * Returns the return value of the invoked method if a class
+                * instance and method has been found. Returns `null` if either
+                * no bound class instance could be found, or if the found
+                * instance didn't have the requested `method`.
                 */
-               require: function(name, from) {
-                       var L = this, url = null, from = from || [];
+               callClassMethod: function(node, method /*, ... */) {
+                       var inst = this.findClassInstance(node);
 
-                       /* Class already loaded */
-                       if (classes[name] != null) {
-                               /* Circular dependency */
-                               if (from.indexOf(name) != -1)
-                                       L.raise('DependencyError',
-                                               'Circular dependency: class "%s" depends on "%s"',
-                                               name, from.join('" which depends on "'));
+                       if (inst == null || typeof(inst[method]) != 'function')
+                               return null;
 
-                               return Promise.resolve(classes[name]);
-                       }
+                       return inst[method].apply(inst, inst.varargs(arguments, 2));
+               },
 
-                       url = '%s/%s.js%s'.format(L.env.base_url, name.replace(/\./g, '/'), (L.env.resource_version ? '?v=' + L.env.resource_version : ''));
-                       from = [ name ].concat(from);
+               /**
+                * The ignore callback function is invoked by `isEmpty()` for each
+                * child node to decide whether to ignore a child node or not.
+                *
+                * When this function returns `false`, the node passed to it is
+                * ignored, else not.
+                *
+                * @callback LuCI.dom~ignoreCallbackFn
+                * @param {Node} node
+                * The child node to test.
+                *
+                * @returns {boolean}
+                * Boolean indicating whether to ignore the node or not.
+                */
 
-                       var compileClass = function(res) {
-                               if (!res.ok)
-                                       L.raise('NetworkError',
-                                               'HTTP error %d while loading class file "%s"', res.status, url);
+               /**
+                * Tests whether a given DOM `Node` instance is empty or appears
+                * empty.
+                *
+                * Any element child nodes which have the CSS class `hidden` set
+                * or for which the optionally passed `ignoreFn` callback function
+                * returns `false` are ignored.
+                *
+                * @instance
+                * @memberof LuCI.dom
+                * @param {Node} node
+                * The DOM `Node` instance to test.
+                *
+                * @param {LuCI.dom~ignoreCallbackFn} [ignoreFn]
+                * Specifies an optional function which is invoked for each child
+                * node to decide whether the child node should be ignored or not.
+                *
+                * @returns {boolean}
+                * Returns `true` if the node does not have any children or if
+                * any children node either has a `hidden` CSS class or a `false`
+                * result when testing it using the given `ignoreFn`.
+                */
+               isEmpty: function(node, ignoreFn) {
+                       for (var child = node.firstElementChild; child != null; child = child.nextElementSibling)
+                               if (!child.classList.contains('hidden') && (!ignoreFn || !ignoreFn(child)))
+                                       return false;
 
-                               var source = res.text(),
-                                   requirematch = /^require[ \t]+(\S+)(?:[ \t]+as[ \t]+([a-zA-Z_]\S*))?$/,
-                                   strictmatch = /^use[ \t]+strict$/,
-                                   depends = [],
-                                   args = '';
+                       return true;
+               }
+       });
 
-                               /* find require statements in source */
-                               for (var i = 0, off = -1, quote = -1, esc = false; i < source.length; i++) {
-                                       var chr = source.charCodeAt(i);
+       /**
+        * @class session
+        * @memberof LuCI
+        * @hideconstructor
+        * @classdesc
+        *
+        * The `session` class provides various session related functionality.
+        */
+       var Session = Class.singleton(/** @lends LuCI.session.prototype */ {
+               __name__: 'LuCI.session',
 
-                                       if (esc) {
-                                               esc = false;
-                                       }
-                                       else if (chr == 92) {
-                                               esc = true;
-                                       }
-                                       else if (chr == quote) {
-                                               var s = source.substring(off, i),
-                                                   m = requirematch.exec(s);
+               /**
+                * Retrieve the current session ID.
+                *
+                * @returns {string}
+                * Returns the current session ID.
+                */
+               getID: function() {
+                       return env.sessionid || '00000000000000000000000000000000';
+               },
 
-                                               if (m) {
-                                                       var dep = m[1], as = m[2] || dep.replace(/[^a-zA-Z0-9_]/g, '_');
-                                                       depends.push(L.require(dep, from));
-                                                       args += ', ' + as;
-                                               }
-                                               else if (!strictmatch.exec(s)) {
-                                                       break;
-                                               }
+               /**
+                * Retrieve the current session token.
+                *
+                * @returns {string|null}
+                * Returns the current session token or `null` if not logged in.
+                */
+               getToken: function() {
+                       return env.token || null;
+               },
 
-                                               off = -1;
-                                               quote = -1;
-                                       }
-                                       else if (quote == -1 && (chr == 34 || chr == 39)) {
-                                               off = i + 1;
-                                               quote = chr;
-                                       }
+               /**
+                * Retrieve data from the local session storage.
+                *
+                * @param {string} [key]
+                * The key to retrieve from the session data store. If omitted, all
+                * session data will be returned.
+                *
+                * @returns {*}
+                * Returns the stored session data or `null` if the given key wasn't
+                * found.
+                */
+               getLocalData: function(key) {
+                       try {
+                               var sid = this.getID(),
+                                   item = 'luci-session-store',
+                                   data = JSON.parse(window.sessionStorage.getItem(item));
+
+                               if (!LuCI.prototype.isObject(data) || !data.hasOwnProperty(sid)) {
+                                       data = {};
+                                       data[sid] = {};
                                }
 
-                               /* load dependencies and instantiate class */
-                               return Promise.all(depends).then(function(instances) {
-                                       var _factory, _class;
+                               if (key != null)
+                                       return data[sid].hasOwnProperty(key) ? data[sid][key] : null;
 
-                                       try {
-                                               _factory = eval(
-                                                       '(function(window, document, L%s) { %s })\n\n//# sourceURL=%s\n'
-                                                               .format(args, source, res.url));
-                                       }
-                                       catch (error) {
-                                               L.raise('SyntaxError', '%s\n  in %s:%s',
-                                                       error.message, res.url, error.lineNumber || '?');
-                                       }
+                               return data[sid];
+                       }
+                       catch (e) {
+                               return (key != null) ? null : {};
+                       }
+               },
 
-                                       _factory.displayName = toCamelCase(name + 'ClassFactory');
-                                       _class = _factory.apply(_factory, [window, document, L].concat(instances));
+               /**
+                * Set data in the local session storage.
+                *
+                * @param {string} key
+                * The key to set in the session data store.
+                *
+                * @param {*} value
+                * The value to store. It will be internally converted to JSON before
+                * being put in the session store.
+                *
+                * @returns {boolean}
+                * Returns `true` if the data could be stored or `false` on error.
+                */
+               setLocalData: function(key, value) {
+                       if (key == null)
+                               return false;
 
-                                       if (!Class.isSubclass(_class))
-                                           L.error('TypeError', '"%s" factory yields invalid constructor', name);
+                       try {
+                               var sid = this.getID(),
+                                   item = 'luci-session-store',
+                                   data = JSON.parse(window.sessionStorage.getItem(item));
 
-                                       if (_class.displayName == 'AnonymousClass')
-                                               _class.displayName = toCamelCase(name + 'Class');
+                               if (!LuCI.prototype.isObject(data) || !data.hasOwnProperty(sid)) {
+                                       data = {};
+                                       data[sid] = {};
+                               }
 
-                                       var ptr = Object.getPrototypeOf(L),
-                                           parts = name.split(/\./),
-                                           instance = new _class();
+                               if (value != null)
+                                       data[sid][key] = value;
+                               else
+                                       delete data[sid][key];
 
-                                       for (var i = 0; ptr && i < parts.length - 1; i++)
-                                               ptr = ptr[parts[i]];
+                               window.sessionStorage.setItem(item, JSON.stringify(data));
 
-                                       if (ptr)
-                                               ptr[parts[i]] = instance;
+                               return true;
+                       }
+                       catch (e) {
+                               return false;
+                       }
+               }
+       });
 
-                                       classes[name] = instance;
+       /**
+        * @class view
+        * @memberof LuCI
+        * @hideconstructor
+        * @classdesc
+        *
+        * The `view` class forms the basis of views and provides a standard
+        * set of methods to inherit from.
+        */
+       var View = Class.extend(/** @lends LuCI.view.prototype */ {
+               __name__: 'LuCI.view',
 
-                                       return instance;
-                               });
-                       };
+               __init__: function() {
+                       var vp = document.getElementById('view');
 
-                       /* Request class file */
-                       classes[name] = Request.get(url, { cache: true }).then(compileClass);
+                       DOM.content(vp, E('div', { 'class': 'spinning' }, _('Loading view…')));
 
-                       return classes[name];
+                       return Promise.resolve(this.load())
+                               .then(LuCI.prototype.bind(this.render, this))
+                               .then(LuCI.prototype.bind(function(nodes) {
+                                       var vp = document.getElementById('view');
+
+                                       DOM.content(vp, nodes);
+                                       DOM.append(vp, this.addFooter());
+                               }, this)).catch(LuCI.prototype.error);
                },
 
-               /* DOM setup */
-               probeRPCBaseURL: function() {
-                       if (rpcBaseURL == null) {
-                               try {
-                                       rpcBaseURL = window.sessionStorage.getItem('rpcBaseURL');
-                               }
-                               catch (e) { }
-                       }
+               /**
+                * The load function is invoked before the view is rendered.
+                *
+                * The invocation of this function is wrapped by
+                * `Promise.resolve()` so it may return Promises if needed.
+                *
+                * The return value of the function (or the resolved values
+                * of the promise returned by it) will be passed as first
+                * argument to `render()`.
+                *
+                * This function is supposed to be overwritten by subclasses,
+                * the default implementation does nothing.
+                *
+                * @instance
+                * @abstract
+                * @memberof LuCI.view
+                *
+                * @returns {*|Promise<*>}
+                * May return any value or a Promise resolving to any value.
+                */
+               load: function() {},
 
-                       if (rpcBaseURL == null) {
-                               var rpcFallbackURL = this.url('admin/ubus');
+               /**
+                * The render function is invoked after the
+                * {@link LuCI.view#load load()} function and responsible
+                * for setting up the view contents. It must return a DOM
+                * `Node` or `DocumentFragment` holding the contents to
+                * insert into the view area.
+                *
+                * The invocation of this function is wrapped by
+                * `Promise.resolve()` so it may return Promises if needed.
+                *
+                * The return value of the function (or the resolved values
+                * of the promise returned by it) will be inserted into the
+                * main content area using
+                * {@link LuCI.dom#append dom.append()}.
+                *
+                * This function is supposed to be overwritten by subclasses,
+                * the default implementation does nothing.
+                *
+                * @instance
+                * @abstract
+                * @memberof LuCI.view
+                * @param {*|null} load_results
+                * This function will receive the return value of the
+                * {@link LuCI.view#load view.load()} function as first
+                * argument.
+                *
+                * @returns {Node|Promise<Node>}
+                * Should return a DOM `Node` value or a `Promise` resolving
+                * to a `Node` value.
+                */
+               render: function() {},
 
-                               rpcBaseURL = Request.get(this.env.ubuspath).then(function(res) {
-                                       return (rpcBaseURL = (res.status == 400) ? L.env.ubuspath : rpcFallbackURL);
-                               }, function() {
-                                       return (rpcBaseURL = rpcFallbackURL);
-                               }).then(function(url) {
-                                       try {
-                                               window.sessionStorage.setItem('rpcBaseURL', url);
-                                       }
-                                       catch (e) { }
+               /**
+                * The handleSave function is invoked when the user clicks
+                * the `Save` button in the page action footer.
+                *
+                * The default implementation should be sufficient for most
+                * views using {@link form#Map form.Map()} based forms - it
+                * will iterate all forms present in the view and invoke
+                * the {@link form#Map#save Map.save()} method on each form.
+                *
+                * Views not using `Map` instances or requiring other special
+                * logic should overwrite `handleSave()` with a custom
+                * implementation.
+                *
+                * To disable the `Save` page footer button, views extending
+                * this base class should overwrite the `handleSave` function
+                * with `null`.
+                *
+                * The invocation of this function is wrapped by
+                * `Promise.resolve()` so it may return Promises if needed.
+                *
+                * @instance
+                * @memberof LuCI.view
+                * @param {Event} ev
+                * The DOM event that triggered the function.
+                *
+                * @returns {*|Promise<*>}
+                * Any return values of this function are discarded, but
+                * passed through `Promise.resolve()` to ensure that any
+                * returned promise runs to completion before the button
+                * is reenabled.
+                */
+               handleSave: function(ev) {
+                       var tasks = [];
 
-                                       return url;
+                       document.getElementById('maincontent')
+                               .querySelectorAll('.cbi-map').forEach(function(map) {
+                                       tasks.push(DOM.callClassMethod(map, 'save'));
                                });
-                       }
 
-                       return Promise.resolve(rpcBaseURL);
+                       return Promise.all(tasks);
                },
 
-               probeSystemFeatures: function() {
-                       var sessionid = classes.rpc.getSessionID();
-
-                       if (sysFeatures == null) {
-                               try {
-                                       var data = JSON.parse(window.sessionStorage.getItem('sysFeatures'));
-
-                                       if (this.isObject(data) && this.isObject(data[sessionid]))
-                                               sysFeatures = data[sessionid];
-                               }
-                               catch (e) {}
-                       }
-
-                       if (!this.isObject(sysFeatures)) {
-                               sysFeatures = classes.rpc.declare({
-                                       object: 'luci',
-                                       method: 'getFeatures',
-                                       expect: { '': {} }
-                               })().then(function(features) {
-                                       try {
-                                               var data = {};
-                                                   data[sessionid] = features;
-
-                                               window.sessionStorage.setItem('sysFeatures', JSON.stringify(data));
-                                       }
-                                       catch (e) {}
+               /**
+                * The handleSaveApply function is invoked when the user clicks
+                * the `Save & Apply` button in the page action footer.
+                *
+                * The default implementation should be sufficient for most
+                * views using {@link form#Map form.Map()} based forms - it
+                * will first invoke
+                * {@link LuCI.view.handleSave view.handleSave()} and then
+                * call {@link ui#changes#apply ui.changes.apply()} to start the
+                * modal config apply and page reload flow.
+                *
+                * Views not using `Map` instances or requiring other special
+                * logic should overwrite `handleSaveApply()` with a custom
+                * implementation.
+                *
+                * To disable the `Save & Apply` page footer button, views
+                * extending this base class should overwrite the
+                * `handleSaveApply` function with `null`.
+                *
+                * The invocation of this function is wrapped by
+                * `Promise.resolve()` so it may return Promises if needed.
+                *
+                * @instance
+                * @memberof LuCI.view
+                * @param {Event} ev
+                * The DOM event that triggered the function.
+                *
+                * @returns {*|Promise<*>}
+                * Any return values of this function are discarded, but
+                * passed through `Promise.resolve()` to ensure that any
+                * returned promise runs to completion before the button
+                * is reenabled.
+                */
+               handleSaveApply: function(ev, mode) {
+                       return this.handleSave(ev).then(function() {
+                               classes.ui.changes.apply(mode == '0');
+                       });
+               },
 
-                                       sysFeatures = features;
+               /**
+                * The handleReset function is invoked when the user clicks
+                * the `Reset` button in the page action footer.
+                *
+                * The default implementation should be sufficient for most
+                * views using {@link form#Map form.Map()} based forms - it
+                * will iterate all forms present in the view and invoke
+                * the {@link form#Map#save Map.reset()} method on each form.
+                *
+                * Views not using `Map` instances or requiring other special
+                * logic should overwrite `handleReset()` with a custom
+                * implementation.
+                *
+                * To disable the `Reset` page footer button, views extending
+                * this base class should overwrite the `handleReset` function
+                * with `null`.
+                *
+                * The invocation of this function is wrapped by
+                * `Promise.resolve()` so it may return Promises if needed.
+                *
+                * @instance
+                * @memberof LuCI.view
+                * @param {Event} ev
+                * The DOM event that triggered the function.
+                *
+                * @returns {*|Promise<*>}
+                * Any return values of this function are discarded, but
+                * passed through `Promise.resolve()` to ensure that any
+                * returned promise runs to completion before the button
+                * is reenabled.
+                */
+               handleReset: function(ev) {
+                       var tasks = [];
 
-                                       return features;
+                       document.getElementById('maincontent')
+                               .querySelectorAll('.cbi-map').forEach(function(map) {
+                                       tasks.push(DOM.callClassMethod(map, 'reset'));
                                });
-                       }
 
-                       return Promise.resolve(sysFeatures);
+                       return Promise.all(tasks);
                },
 
                /**
-                * Test whether a particular system feature is available, such as
-                * hostapd SAE support or an installed firewall. The features are
-                * queried once at the beginning of the LuCI session and cached in
-                * `SessionStorage` throughout the lifetime of the associated tab or
-                * browser window.
-                *
-                * @instance
-                * @memberof LuCI
+                * Renders a standard page action footer if any of the
+                * `handleSave()`, `handleSaveApply()` or `handleReset()`
+                * functions are defined.
                 *
-                * @param {string} feature
-                * The feature to test. For detailed list of known feature flags,
-                * see `/modules/luci-base/root/usr/libexec/rpcd/luci`.
+                * The default implementation should be sufficient for most
+                * views - it will render a standard page footer with action
+                * buttons labeled `Save`, `Save & Apply` and `Reset`
+                * triggering the `handleSave()`, `handleSaveApply()` and
+                * `handleReset()` functions respectively.
                 *
-                * @param {string} [subfeature]
-                * Some feature classes like `hostapd` provide sub-feature flags,
-                * such as `sae` or `11w` support. The `subfeature` argument can
-                * be used to query these.
+                * When any of these `handle*()` functions is overwritten
+                * with `null` by a view extending this class, the
+                * corresponding button will not be rendered.
                 *
-                * @return {boolean|null}
-                * Return `true` if the queried feature (and sub-feature) is available
-                * or `false` if the requested feature isn't present or known.
-                * Return `null` when a sub-feature was queried for a feature which
-                * has no sub-features.
+                * @instance
+                * @memberof LuCI.view
+                * @returns {DocumentFragment}
+                * Returns a `DocumentFragment` containing the footer bar
+                * with buttons for each corresponding `handle*()` action
+                * or an empty `DocumentFragment` if all three `handle*()`
+                * methods are overwritten with `null`.
                 */
-               hasSystemFeature: function() {
-                       var ft = sysFeatures[arguments[0]];
-
-                       if (arguments.length == 2)
-                               return this.isObject(ft) ? ft[arguments[1]] : null;
-
-                       return (ft != null && ft != false);
-               },
-
-               /* private */
-               notifySessionExpiry: function() {
-                       Poll.stop();
-
-                       L.ui.showModal(_('Session expired'), [
-                               E('div', { class: 'alert-message warning' },
-                                       _('A new login is required since the authentication session expired.')),
-                               E('div', { class: 'right' },
-                                       E('div', {
-                                               class: 'btn primary',
-                                               click: function() {
-                                                       var loc = window.location;
-                                                       window.location = loc.protocol + '//' + loc.host + loc.pathname + loc.search;
-                                               }
-                                       }, _('To login…')))
-                       ]);
+               addFooter: function() {
+                       var footer = E([]),
+                           vp = document.getElementById('view'),
+                           hasmap = false,
+                           readonly = true;
+
+                       vp.querySelectorAll('.cbi-map').forEach(function(map) {
+                               var m = DOM.findClassInstance(map);
+                               if (m) {
+                                       hasmap = true;
+
+                                       if (!m.readonly)
+                                               readonly = false;
+                               }
+                       });
 
-                       L.raise('SessionError', 'Login session is expired');
-               },
+                       if (!hasmap)
+                               readonly = !LuCI.prototype.hasViewPermission();
+
+                       var saveApplyBtn = this.handleSaveApply ? new classes.ui.ComboButton('0', {
+                               0: [ _('Save & Apply') ],
+                               1: [ _('Apply unchecked') ]
+                       }, {
+                               classes: {
+                                       0: 'btn cbi-button cbi-button-apply important',
+                                       1: 'btn cbi-button cbi-button-negative important'
+                               },
+                               click: classes.ui.createHandlerFn(this, 'handleSaveApply'),
+                               disabled: readonly || null
+                       }).render() : E([]);
+
+                       if (this.handleSaveApply || this.handleSave || this.handleReset) {
+                               footer.appendChild(E('div', { 'class': 'cbi-page-actions control-group' }, [
+                                       saveApplyBtn, ' ',
+                                       this.handleSave ? E('button', {
+                                               'class': 'cbi-button cbi-button-save',
+                                               'click': classes.ui.createHandlerFn(this, 'handleSave'),
+                                               'disabled': readonly || null
+                                       }, [ _('Save') ]) : '', ' ',
+                                       this.handleReset ? E('button', {
+                                               'class': 'cbi-button cbi-button-reset',
+                                               'click': classes.ui.createHandlerFn(this, 'handleReset'),
+                                               'disabled': readonly || null
+                                       }, [ _('Reset') ]) : ''
+                               ]));
+                       }
 
-               /* private */
-               setupDOM: function(res) {
-                       var domEv = res[0],
-                           uiClass = res[1],
-                           rpcClass = res[2],
-                           formClass = res[3],
-                           rpcBaseURL = res[4];
+                       return footer;
+               }
+       });
 
-                       rpcClass.setBaseURL(rpcBaseURL);
 
-                       rpcClass.addInterceptor(function(msg, req) {
-                               if (!L.isObject(msg) || !L.isObject(msg.error) || msg.error.code != -32002)
-                                       return;
+       var dummyElem = null,
+           domParser = null,
+           originalCBIInit = null,
+           rpcBaseURL = null,
+           sysFeatures = null,
+           preloadClasses = null;
+
+       /* "preload" builtin classes to make the available via require */
+       var classes = {
+               baseclass: Class,
+               dom: DOM,
+               poll: Poll,
+               request: Request,
+               session: Session,
+               view: View
+       };
 
-                               if (!L.isObject(req) || (req.object == 'session' && req.method == 'access'))
-                                       return;
+       var LuCI = Class.extend(/** @lends LuCI.prototype */ {
+               __name__: 'LuCI',
+               __init__: function(setenv) {
 
-                               return rpcClass.declare({
-                                       'object': 'session',
-                                       'method': 'access',
-                                       'params': [ 'scope', 'object', 'function' ],
-                                       'expect': { access: true }
-                               })('uci', 'luci', 'read').catch(L.notifySessionExpiry);
+                       document.querySelectorAll('script[src*="/luci.js"]').forEach(function(s) {
+                               if (setenv.base_url == null || setenv.base_url == '') {
+                                       var m = (s.getAttribute('src') || '').match(/^(.*)\/luci\.js(?:\?v=([^?]+))?$/);
+                                       if (m) {
+                                               setenv.base_url = m[1];
+                                               setenv.resource_version = m[2];
+                                       }
+                               }
                        });
 
-                       Request.addInterceptor(function(res) {
-                               var isDenied = false;
+                       if (setenv.base_url == null)
+                               this.error('InternalError', 'Cannot find url of luci.js');
 
-                               if (res.status == 403 && res.headers.get('X-LuCI-Login-Required') == 'yes')
-                                       isDenied = true;
+                       setenv.cgi_base = setenv.scriptname.replace(/\/[^\/]+$/, '');
 
-                               if (!isDenied)
-                                       return;
+                       Object.assign(env, setenv);
 
-                               L.notifySessionExpiry();
+                       var domReady = new Promise(function(resolveFn, rejectFn) {
+                               document.addEventListener('DOMContentLoaded', resolveFn);
                        });
 
-                       return this.probeSystemFeatures().finally(this.initDOM);
-               },
+                       Promise.all([
+                               domReady,
+                               this.require('ui'),
+                               this.require('rpc'),
+                               this.require('form'),
+                               this.probeRPCBaseURL()
+                       ]).then(this.setupDOM.bind(this)).catch(this.error);
 
-               /* private */
-               initDOM: function() {
-                       originalCBIInit();
-                       Poll.start();
-                       document.dispatchEvent(new CustomEvent('luci-loaded'));
+                       originalCBIInit = window.cbi_init;
+                       window.cbi_init = function() {};
                },
 
                /**
-                * The `env` object holds environment settings used by LuCI, such
-                * as request timeouts, base URLs etc.
+                * Captures the current stack trace and throws an error of the
+                * specified type as a new exception. Also logs the exception as
+                * error to the debug console if it is available.
                 *
                 * @instance
                 * @memberof LuCI
-                */
-               env: {},
-
-               /**
-                * Construct a relative URL path from the given prefix and parts.
-                * The resulting URL is guaranteed to only contain the characters
-                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
-                * as `/` for the path separator.
                 *
-                * @instance
-                * @memberof LuCI
+                * @param {Error|string} [type=Error]
+                * Either a string specifying the type of the error to throw or an
+                * existing `Error` instance to copy.
                 *
-                * @param {string} [prefix]
-                * The prefix to join the given parts with. If the `prefix` is
-                * omitted, it defaults to an empty string.
+                * @param {string} [fmt=Unspecified error]
+                * A format string which is used to form the error message, together
+                * with all subsequent optional arguments.
                 *
-                * @param {string[]} [parts]
-                * An array of parts to join into an URL path. Parts may contain
-                * slashes and any of the other characters mentioned above.
+                * @param {...*} [args]
+                * Zero or more variable arguments to the supplied format string.
                 *
-                * @return {string}
-                * Return the joined URL path.
+                * @throws {Error}
+                * Throws the created error object with the captured stack trace
+                * appended to the message and the type set to the given type
+                * argument or copied from the given error instance.
                 */
-               path: function(prefix, parts) {
-                       var url = [ prefix || '' ];
+               raise: function(type, fmt /*, ...*/) {
+                       var e = null,
+                           msg = fmt ? String.prototype.format.apply(fmt, this.varargs(arguments, 2)) : null,
+                           stack = null;
 
-                       for (var i = 0; i < parts.length; i++)
-                               if (/^(?:[a-zA-Z0-9_.%,;-]+\/)*[a-zA-Z0-9_.%,;-]+$/.test(parts[i]))
-                                       url.push('/', parts[i]);
+                       if (type instanceof Error) {
+                               e = type;
 
-                       if (url.length === 1)
-                               url.push('/');
+                               if (msg)
+                                       e.message = msg + ': ' + e.message;
+                       }
+                       else {
+                               try { throw new Error('stacktrace') }
+                               catch (e2) { stack = (e2.stack || '').split(/\n/) }
 
-                       return url.join('');
+                               e = new (window[type || 'Error'] || Error)(msg || 'Unspecified error');
+                               e.name = type || 'Error';
+                       }
+
+                       stack = (stack || []).map(function(frame) {
+                               frame = frame.replace(/(.*?)@(.+):(\d+):(\d+)/g, 'at $1 ($2:$3:$4)').trim();
+                               return frame ? '  ' + frame : '';
+                       });
+
+                       if (!/^  at /.test(stack[0]))
+                               stack.shift();
+
+                       if (/\braise /.test(stack[0]))
+                               stack.shift();
+
+                       if (/\berror /.test(stack[0]))
+                               stack.shift();
+
+                       if (stack.length)
+                               e.message += '\n' + stack.join('\n');
+
+                       if (window.console && console.debug)
+                               console.debug(e);
+
+                       throw e;
                },
 
                /**
-                * Construct an URL  pathrelative to the script path of the server
-                * side LuCI application (usually `/cgi-bin/luci`).
-                *
-                * The resulting URL is guaranteed to only contain the characters
-                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
-                * as `/` for the path separator.
+                * A wrapper around {@link LuCI#raise raise()} which also renders
+                * the error either as modal overlay when `ui.js` is already loaed
+                * or directly into the view body.
                 *
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {string[]} [parts]
-                * An array of parts to join into an URL path. Parts may contain
-                * slashes and any of the other characters mentioned above.
+                * @param {Error|string} [type=Error]
+                * Either a string specifying the type of the error to throw or an
+                * existing `Error` instance to copy.
                 *
-                * @return {string}
-                * Returns the resulting URL path.
+                * @param {string} [fmt=Unspecified error]
+                * A format string which is used to form the error message, together
+                * with all subsequent optional arguments.
+                *
+                * @param {...*} [args]
+                * Zero or more variable arguments to the supplied format string.
+                *
+                * @throws {Error}
+                * Throws the created error object with the captured stack trace
+                * appended to the message and the type set to the given type
+                * argument or copied from the given error instance.
                 */
-               url: function() {
-                       return this.path(this.env.scriptname, arguments);
+               error: function(type, fmt /*, ...*/) {
+                       try {
+                               LuCI.prototype.raise.apply(LuCI.prototype,
+                                       Array.prototype.slice.call(arguments));
+                       }
+                       catch (e) {
+                               if (!e.reported) {
+                                       if (classes.ui)
+                                               classes.ui.addNotification(e.name || _('Runtime error'),
+                                                       E('pre', {}, e.message), 'danger');
+                                       else
+                                               DOM.content(document.querySelector('#maincontent'),
+                                                       E('pre', { 'class': 'alert-message error' }, e.message));
+
+                                       e.reported = true;
+                               }
+
+                               throw e;
+                       }
                },
 
                /**
-                * Construct an URL path relative to the global static resource path
-                * of the LuCI ui (usually `/luci-static/resources`).
-                *
-                * The resulting URL is guaranteed to only contain the characters
-                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
-                * as `/` for the path separator.
+                * Return a bound function using the given `self` as `this` context
+                * and any further arguments as parameters to the bound function.
                 *
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {string[]} [parts]
-                * An array of parts to join into an URL path. Parts may contain
-                * slashes and any of the other characters mentioned above.
+                * @param {function} fn
+                * The function to bind.
                 *
-                * @return {string}
-                * Returns the resulting URL path.
+                * @param {*} self
+                * The value to bind as `this` context to the specified function.
+                *
+                * @param {...*} [args]
+                * Zero or more variable arguments which are bound to the function
+                * as parameters.
+                *
+                * @returns {function}
+                * Returns the bound function.
                 */
-               resource: function() {
-                       return this.path(this.env.resource, arguments);
+               bind: function(fn, self /*, ... */) {
+                       return Function.prototype.bind.apply(fn, this.varargs(arguments, 2, self));
                },
 
                /**
-                * Return the complete URL path to the current view.
+                * Load an additional LuCI JavaScript class and its dependencies,
+                * instantiate it and return the resulting class instance. Each
+                * class is only loaded once. Subsequent attempts to load the same
+                * class will return the already instantiated class.
                 *
                 * @instance
                 * @memberof LuCI
                 *
-                * @return {string}
-                * Returns the URL path to the current view.
-                */
-               location: function() {
-                       return this.path(this.env.scriptname, this.env.requestpath);
-               },
-
-
-               /**
-                * Tests whether the passed argument is a JavaScript object.
-                * This function is meant to be an object counterpart to the
-                * standard `Array.isArray()` function.
-                *
-                * @instance
-                * @memberof LuCI
-                *
-                * @param {*} [val]
-                * The value to test
-                *
-                * @return {boolean}
-                * Returns `true` if the given value is of type object and
-                * not `null`, else returns `false`.
-                */
-               isObject: function(val) {
-                       return (val != null && typeof(val) == 'object');
-               },
-
-               /**
-                * Return an array of sorted object keys, optionally sorted by
-                * a different key or a different sorting mode.
+                * @param {string} name
+                * The name of the class to load in dotted notation. Dots will
+                * be replaced by spaces and joined with the runtime-determined
+                * base URL of LuCI.js to form an absolute URL to load the class
+                * file from.
                 *
-                * @instance
-                * @memberof LuCI
+                * @throws {DependencyError}
+                * Throws a `DependencyError` when the class to load includes
+                * circular dependencies.
                 *
-                * @param {object} obj
-                * The object to extract the keys from. If the given value is
-                * not an object, the function will return an empty array.
+                * @throws {NetworkError}
+                * Throws `NetworkError` when the underlying {@link LuCI.request}
+                * call failed.
                 *
-                * @param {string} [key]
-                * Specifies the key to order by. This is mainly useful for
-                * nested objects of objects or objects of arrays when sorting
-                * shall not be performed by the primary object keys but by
-                * some other key pointing to a value within the nested values.
+                * @throws {SyntaxError}
+                * Throws `SyntaxError` when the loaded class file code cannot
+                * be interpreted by `eval`.
                 *
-                * @param {string} [sortmode]
-                * May be either `addr` or `num` to override the natural
-                * lexicographic sorting with a sorting suitable for IP/MAC style
-                * addresses or numeric values respectively.
+                * @throws {TypeError}
+                * Throws `TypeError` when the class file could be loaded and
+                * interpreted, but when invoking its code did not yield a valid
+                * class instance.
                 *
-                * @return {string[]}
-                * Returns an array containing the sorted keys of the given object.
+                * @returns {Promise<LuCI.baseclass>}
+                * Returns the instantiated class.
                 */
-               sortedKeys: function(obj, key, sortmode) {
-                       if (obj == null || typeof(obj) != 'object')
-                               return [];
+               require: function(name, from) {
+                       var L = this, url = null, from = from || [];
 
-                       return Object.keys(obj).map(function(e) {
-                               var v = (key != null) ? obj[e][key] : e;
+                       /* Class already loaded */
+                       if (classes[name] != null) {
+                               /* Circular dependency */
+                               if (from.indexOf(name) != -1)
+                                       LuCI.prototype.raise('DependencyError',
+                                               'Circular dependency: class "%s" depends on "%s"',
+                                               name, from.join('" which depends on "'));
 
-                               switch (sortmode) {
-                               case 'addr':
-                                       v = (v != null) ? v.replace(/(?:^|[.:])([0-9a-fA-F]{1,4})/g,
-                                               function(m0, m1) { return ('000' + m1.toLowerCase()).substr(-4) }) : null;
-                                       break;
+                               return Promise.resolve(classes[name]);
+                       }
 
-                               case 'num':
-                                       v = (v != null) ? +v : null;
-                                       break;
+                       url = '%s/%s.js%s'.format(env.base_url, name.replace(/\./g, '/'), (env.resource_version ? '?v=' + env.resource_version : ''));
+                       from = [ name ].concat(from);
+
+                       var compileClass = function(res) {
+                               if (!res.ok)
+                                       LuCI.prototype.raise('NetworkError',
+                                               'HTTP error %d while loading class file "%s"', res.status, url);
+
+                               var source = res.text(),
+                                   requirematch = /^require[ \t]+(\S+)(?:[ \t]+as[ \t]+([a-zA-Z_]\S*))?$/,
+                                   strictmatch = /^use[ \t]+strict$/,
+                                   depends = [],
+                                   args = '';
+
+                               /* find require statements in source */
+                               for (var i = 0, off = -1, quote = -1, esc = false; i < source.length; i++) {
+                                       var chr = source.charCodeAt(i);
+
+                                       if (esc) {
+                                               esc = false;
+                                       }
+                                       else if (chr == 92) {
+                                               esc = true;
+                                       }
+                                       else if (chr == quote) {
+                                               var s = source.substring(off, i),
+                                                   m = requirematch.exec(s);
+
+                                               if (m) {
+                                                       var dep = m[1], as = m[2] || dep.replace(/[^a-zA-Z0-9_]/g, '_');
+                                                       depends.push(LuCI.prototype.require(dep, from));
+                                                       args += ', ' + as;
+                                               }
+                                               else if (!strictmatch.exec(s)) {
+                                                       break;
+                                               }
+
+                                               off = -1;
+                                               quote = -1;
+                                       }
+                                       else if (quote == -1 && (chr == 34 || chr == 39)) {
+                                               off = i + 1;
+                                               quote = chr;
+                                       }
                                }
 
-                               return [ e, v ];
-                       }).filter(function(e) {
-                               return (e[1] != null);
-                       }).sort(function(a, b) {
-                               return (a[1] > b[1]);
-                       }).map(function(e) {
-                               return e[0];
-                       });
+                               /* load dependencies and instantiate class */
+                               return Promise.all(depends).then(function(instances) {
+                                       var _factory, _class;
+
+                                       try {
+                                               _factory = eval(
+                                                       '(function(window, document, L%s) { %s })\n\n//# sourceURL=%s\n'
+                                                               .format(args, source, res.url));
+                                       }
+                                       catch (error) {
+                                               LuCI.prototype.raise('SyntaxError', '%s\n  in %s:%s',
+                                                       error.message, res.url, error.lineNumber || '?');
+                                       }
+
+                                       _factory.displayName = toCamelCase(name + 'ClassFactory');
+                                       _class = _factory.apply(_factory, [window, document, L].concat(instances));
+
+                                       if (!Class.isSubclass(_class))
+                                           LuCI.prototype.error('TypeError', '"%s" factory yields invalid constructor', name);
+
+                                       if (_class.displayName == 'AnonymousClass')
+                                               _class.displayName = toCamelCase(name + 'Class');
+
+                                       var ptr = Object.getPrototypeOf(L),
+                                           parts = name.split(/\./),
+                                           instance = new _class();
+
+                                       for (var i = 0; ptr && i < parts.length - 1; i++)
+                                               ptr = ptr[parts[i]];
+
+                                       if (ptr)
+                                               ptr[parts[i]] = instance;
+
+                                       classes[name] = instance;
+
+                                       return instance;
+                               });
+                       };
+
+                       /* Request class file */
+                       classes[name] = Request.get(url, { cache: true }).then(compileClass);
+
+                       return classes[name];
                },
 
-               /**
-                * Converts the given value to an array. If the given value is of
-                * type array, it is returned as-is, values of type object are
-                * returned as one-element array containing the object, empty
-                * strings and `null` values are returned as empty array, all other
-                * values are converted using `String()`, trimmed, split on white
-                * space and returned as array.
-                *
-                * @instance
-                * @memberof LuCI
-                *
-                * @param {*} val
-                * The value to convert into an array.
-                *
-                * @return {Array<*>}
-                * Returns the resulting array.
-                */
-               toArray: function(val) {
-                       if (val == null)
-                               return [];
-                       else if (Array.isArray(val))
-                               return val;
-                       else if (typeof(val) == 'object')
-                               return [ val ];
+               /* DOM setup */
+               probeRPCBaseURL: function() {
+                       if (rpcBaseURL == null)
+                               rpcBaseURL = Session.getLocalData('rpcBaseURL');
 
-                       var s = String(val).trim();
+                       if (rpcBaseURL == null) {
+                               var rpcFallbackURL = this.url('admin/ubus');
 
-                       if (s == '')
-                               return [];
+                               rpcBaseURL = Request.get(env.ubuspath).then(function(res) {
+                                       return (rpcBaseURL = (res.status == 400) ? env.ubuspath : rpcFallbackURL);
+                               }, function() {
+                                       return (rpcBaseURL = rpcFallbackURL);
+                               }).then(function(url) {
+                                       Session.setLocalData('rpcBaseURL', url);
+                                       return url;
+                               });
+                       }
 
-                       return s.split(/\s+/);
+                       return Promise.resolve(rpcBaseURL);
+               },
+
+               probeSystemFeatures: function() {
+                       if (sysFeatures == null)
+                               sysFeatures = Session.getLocalData('features');
+
+                       if (!this.isObject(sysFeatures)) {
+                               sysFeatures = classes.rpc.declare({
+                                       object: 'luci',
+                                       method: 'getFeatures',
+                                       expect: { '': {} }
+                               })().then(function(features) {
+                                       Session.setLocalData('features', features);
+                                       sysFeatures = features;
+
+                                       return features;
+                               });
+                       }
+
+                       return Promise.resolve(sysFeatures);
+               },
+
+               probePreloadClasses: function() {
+                       if (preloadClasses == null)
+                               preloadClasses = Session.getLocalData('preload');
+
+                       if (!Array.isArray(preloadClasses)) {
+                               preloadClasses = this.resolveDefault(classes.rpc.declare({
+                                       object: 'file',
+                                       method: 'list',
+                                       params: [ 'path' ],
+                                       expect: { 'entries': [] }
+                               })(this.fspath(this.resource('preload'))), []).then(function(entries) {
+                                       var classes = [];
+
+                                       for (var i = 0; i < entries.length; i++) {
+                                               if (entries[i].type != 'file')
+                                                       continue;
+
+                                               var m = entries[i].name.match(/(.+)\.js$/);
+
+                                               if (m)
+                                                       classes.push('preload.%s'.format(m[1]));
+                                       }
+
+                                       Session.setLocalData('preload', classes);
+                                       preloadClasses = classes;
+
+                                       return classes;
+                               });
+                       }
+
+                       return Promise.resolve(preloadClasses);
                },
 
                /**
-                * Returns a promise resolving with either the given value or or with
-                * the given default in case the input value is a rejecting promise.
+                * Test whether a particular system feature is available, such as
+                * hostapd SAE support or an installed firewall. The features are
+                * queried once at the beginning of the LuCI session and cached in
+                * `SessionStorage` throughout the lifetime of the associated tab or
+                * browser window.
                 *
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {*} value
-                * The value to resolve the promise with.
+                * @param {string} feature
+                * The feature to test. For detailed list of known feature flags,
+                * see `/modules/luci-base/root/usr/libexec/rpcd/luci`.
                 *
-                * @param {*} defvalue
-                * The default value to resolve the promise with in case the given
-                * input value is a rejecting promise.
+                * @param {string} [subfeature]
+                * Some feature classes like `hostapd` provide sub-feature flags,
+                * such as `sae` or `11w` support. The `subfeature` argument can
+                * be used to query these.
                 *
-                * @returns {Promise<*>}
-                * Returns a new promise resolving either to the given input value or
-                * to the given default value on error.
+                * @return {boolean|null}
+                * Return `true` if the queried feature (and sub-feature) is available
+                * or `false` if the requested feature isn't present or known.
+                * Return `null` when a sub-feature was queried for a feature which
+                * has no sub-features.
                 */
-               resolveDefault: function(value, defvalue) {
-                       return Promise.resolve(value).catch(function() { return defvalue });
+               hasSystemFeature: function() {
+                       var ft = sysFeatures[arguments[0]];
+
+                       if (arguments.length == 2)
+                               return this.isObject(ft) ? ft[arguments[1]] : null;
+
+                       return (ft != null && ft != false);
+               },
+
+               /* private */
+               notifySessionExpiry: function() {
+                       Poll.stop();
+
+                       classes.ui.showModal(_('Session expired'), [
+                               E('div', { class: 'alert-message warning' },
+                                       _('A new login is required since the authentication session expired.')),
+                               E('div', { class: 'right' },
+                                       E('div', {
+                                               class: 'btn primary',
+                                               click: function() {
+                                                       var loc = window.location;
+                                                       window.location = loc.protocol + '//' + loc.host + loc.pathname + loc.search;
+                                               }
+                                       }, _('To login…')))
+                       ]);
+
+                       LuCI.prototype.raise('SessionError', 'Login session is expired');
+               },
+
+               /* private */
+               setupDOM: function(res) {
+                       var domEv = res[0],
+                           uiClass = res[1],
+                           rpcClass = res[2],
+                           formClass = res[3],
+                           rpcBaseURL = res[4];
+
+                       rpcClass.setBaseURL(rpcBaseURL);
+
+                       rpcClass.addInterceptor(function(msg, req) {
+                               if (!LuCI.prototype.isObject(msg) ||
+                                   !LuCI.prototype.isObject(msg.error) ||
+                                   msg.error.code != -32002)
+                                       return;
+
+                               if (!LuCI.prototype.isObject(req) ||
+                                   (req.object == 'session' && req.method == 'access'))
+                                       return;
+
+                               return rpcClass.declare({
+                                       'object': 'session',
+                                       'method': 'access',
+                                       'params': [ 'scope', 'object', 'function' ],
+                                       'expect': { access: true }
+                               })('uci', 'luci', 'read').catch(LuCI.prototype.notifySessionExpiry);
+                       });
+
+                       Request.addInterceptor(function(res) {
+                               var isDenied = false;
+
+                               if (res.status == 403 && res.headers.get('X-LuCI-Login-Required') == 'yes')
+                                       isDenied = true;
+
+                               if (!isDenied)
+                                       return;
+
+                               LuCI.prototype.notifySessionExpiry();
+                       });
+
+                       document.addEventListener('poll-start', function(ev) {
+                               uiClass.showIndicator('poll-status', _('Refreshing'), function(ev) {
+                                       Request.poll.active() ? Request.poll.stop() : Request.poll.start();
+                               });
+                       });
+
+                       document.addEventListener('poll-stop', function(ev) {
+                               uiClass.showIndicator('poll-status', _('Paused'), null, 'inactive');
+                       });
+
+                       return Promise.all([
+                               this.probeSystemFeatures(),
+                               this.probePreloadClasses()
+                       ]).finally(LuCI.prototype.bind(function() {
+                               var tasks = [];
+
+                               if (Array.isArray(preloadClasses))
+                                       for (var i = 0; i < preloadClasses.length; i++)
+                                               tasks.push(this.require(preloadClasses[i]));
+
+                               return Promise.all(tasks);
+                       }, this)).finally(this.initDOM);
+               },
+
+               /* private */
+               initDOM: function() {
+                       originalCBIInit();
+                       Poll.start();
+                       document.dispatchEvent(new CustomEvent('luci-loaded'));
                },
 
                /**
-                * The request callback function is invoked whenever an HTTP
-                * reply to a request made using the `L.get()`, `L.post()` or
-                * `L.poll()` function is timed out or received successfully.
+                * The `env` object holds environment settings used by LuCI, such
+                * as request timeouts, base URLs etc.
                 *
                 * @instance
                 * @memberof LuCI
-                *
-                * @callback LuCI.requestCallbackFn
-                * @param {XMLHTTPRequest} xhr
-                * The XMLHTTPRequest instance used to make the request.
-                *
-                * @param {*} data
-                * The response JSON if the response could be parsed as such,
-                * else `null`.
-                *
-                * @param {number} duration
-                * The total duration of the request in milliseconds.
                 */
+               env: env,
 
                /**
-                * Issues a GET request to the given url and invokes the specified
-                * callback function. The function is a wrapper around
-                * {@link LuCI.Request#request Request.request()}.
+                * Construct an absolute filesystem path relative to the server
+                * document root.
                 *
-                * @deprecated
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {string} url
-                * The URL to request.
-                *
-                * @param {Object<string, string>} [args]
-                * Additional query string arguments to append to the URL.
-                *
-                * @param {LuCI.requestCallbackFn} cb
-                * The callback function to invoke when the request finishes.
+                * @param {...string} [parts]
+                * An array of parts to join into a path.
                 *
-                * @return {Promise<null>}
-                * Returns a promise resolving to `null` when concluded.
+                * @return {string}
+                * Return the joined path.
                 */
-               get: function(url, args, cb) {
-                       return this.poll(null, url, args, cb, false);
+               fspath: function(/* ... */) {
+                       var path = env.documentroot;
+
+                       for (var i = 0; i < arguments.length; i++)
+                               path += '/' + arguments[i];
+
+                       var p = path.replace(/\/+$/, '').replace(/\/+/g, '/').split(/\//),
+                           res = [];
+
+                       for (var i = 0; i < p.length; i++)
+                               if (p[i] == '..')
+                                       res.pop();
+                               else if (p[i] != '.')
+                                       res.push(p[i]);
+
+                       return res.join('/');
                },
 
                /**
-                * Issues a POST request to the given url and invokes the specified
-                * callback function. The function is a wrapper around
-                * {@link LuCI.Request#request Request.request()}. The request is
-                * sent using `application/x-www-form-urlencoded` encoding and will
-                * contain a field `token` with the current value of `LuCI.env.token`
-                * by default.
+                * Construct a relative URL path from the given prefix and parts.
+                * The resulting URL is guaranteed to only contain the characters
+                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
+                * as `/` for the path separator.
                 *
-                * @deprecated
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {string} url
-                * The URL to request.
-                *
-                * @param {Object<string, string>} [args]
-                * Additional post arguments to append to the request body.
+                * @param {string} [prefix]
+                * The prefix to join the given parts with. If the `prefix` is
+                * omitted, it defaults to an empty string.
                 *
-                * @param {LuCI.requestCallbackFn} cb
-                * The callback function to invoke when the request finishes.
+                * @param {string[]} [parts]
+                * An array of parts to join into an URL path. Parts may contain
+                * slashes and any of the other characters mentioned above.
                 *
-                * @return {Promise<null>}
-                * Returns a promise resolving to `null` when concluded.
+                * @return {string}
+                * Return the joined URL path.
                 */
-               post: function(url, args, cb) {
-                       return this.poll(null, url, args, cb, true);
+               path: function(prefix, parts) {
+                       var url = [ prefix || '' ];
+
+                       for (var i = 0; i < parts.length; i++)
+                               if (/^(?:[a-zA-Z0-9_.%,;-]+\/)*[a-zA-Z0-9_.%,;-]+$/.test(parts[i]))
+                                       url.push('/', parts[i]);
+
+                       if (url.length === 1)
+                               url.push('/');
+
+                       return url.join('');
                },
 
                /**
-                * Register a polling HTTP request that invokes the specified
-                * callback function. The function is a wrapper around
-                * {@link LuCI.Request.poll#add Request.poll.add()}.
+                * Construct an URL  pathrelative to the script path of the server
+                * side LuCI application (usually `/cgi-bin/luci`).
+                *
+                * The resulting URL is guaranteed to only contain the characters
+                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
+                * as `/` for the path separator.
                 *
-                * @deprecated
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {number} interval
-                * The poll interval to use. If set to a value less than or equal
-                * to `0`, it will default to the global poll interval configured
-                * in `LuCI.env.pollinterval`.
-                *
-                * @param {string} url
-                * The URL to request.
-                *
-                * @param {Object<string, string>} [args]
-                * Specifies additional arguments for the request. For GET requests,
-                * the arguments are appended to the URL as query string, for POST
-                * requests, they'll be added to the request body.
-                *
-                * @param {LuCI.requestCallbackFn} cb
-                * The callback function to invoke whenever a request finishes.
-                *
-                * @param {boolean} [post=false]
-                * When set to `false` or not specified, poll requests will be made
-                * using the GET method. When set to `true`, POST requests will be
-                * issued. In case of POST requests, the request body will contain
-                * an argument `token` with the current value of `LuCI.env.token` by
-                * default, regardless of the parameters specified with `args`.
+                * @param {string[]} [parts]
+                * An array of parts to join into an URL path. Parts may contain
+                * slashes and any of the other characters mentioned above.
                 *
-                * @return {function}
-                * Returns the internally created function that has been passed to
-                * {@link LuCI.Request.poll#add Request.poll.add()}. This value can
-                * be passed to {@link LuCI.Poll.remove Poll.remove()} to remove the
-                * polling request.
+                * @return {string}
+                * Returns the resulting URL path.
                 */
-               poll: function(interval, url, args, cb, post) {
-                       if (interval !== null && interval <= 0)
-                               interval = this.env.pollinterval;
-
-                       var data = post ? { token: this.env.token } : null,
-                           method = post ? 'POST' : 'GET';
-
-                       if (!/^(?:\/|\S+:\/\/)/.test(url))
-                               url = this.url(url);
-
-                       if (args != null)
-                               data = Object.assign(data || {}, args);
-
-                       if (interval !== null)
-                               return Request.poll.add(interval, url, { method: method, query: data }, cb);
-                       else
-                               return Request.request(url, { method: method, query: data })
-                                       .then(function(res) {
-                                               var json = null;
-                                               if (/^application\/json\b/.test(res.headers.get('Content-Type')))
-                                                       try { json = res.json() } catch(e) {}
-                                               cb(res.xhr, json, res.duration);
-                                       });
+               url: function() {
+                       return this.path(env.scriptname, arguments);
                },
 
                /**
-                * Deprecated wrapper around {@link LuCI.Poll.remove Poll.remove()}.
+                * Construct an URL path relative to the global static resource path
+                * of the LuCI ui (usually `/luci-static/resources`).
+                *
+                * The resulting URL is guaranteed to only contain the characters
+                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
+                * as `/` for the path separator.
                 *
-                * @deprecated
                 * @instance
                 * @memberof LuCI
                 *
-                * @param {function} entry
-                * The polling function to remove.
+                * @param {string[]} [parts]
+                * An array of parts to join into an URL path. Parts may contain
+                * slashes and any of the other characters mentioned above.
                 *
-                * @return {boolean}
-                * Returns `true` when the function has been removed or `false` if
-                * it could not be found.
+                * @return {string}
+                * Returns the resulting URL path.
                 */
-               stop: function(entry) { return Poll.remove(entry) },
+               resource: function() {
+                       return this.path(env.resource, arguments);
+               },
 
                /**
-                * Deprecated wrapper around {@link LuCI.Poll.stop Poll.stop()}.
+                * Construct an URL path relative to the media resource path of the
+                * LuCI ui (usually `/luci-static/$theme_name`).
+                *
+                * The resulting URL is guaranteed to only contain the characters
+                * `a-z`, `A-Z`, `0-9`, `_`, `.`, `%`, `,`, `;`, and `-` as well
+                * as `/` for the path separator.
                 *
-                * @deprecated
                 * @instance
                 * @memberof LuCI
                 *
-                * @return {boolean}
-                * Returns `true` when the polling loop has been stopped or `false`
-                * when it didn't run to begin with.
+                * @param {string[]} [parts]
+                * An array of parts to join into an URL path. Parts may contain
+                * slashes and any of the other characters mentioned above.
+                *
+                * @return {string}
+                * Returns the resulting URL path.
                 */
-               halt: function() { return Poll.stop() },
+               media: function() {
+                       return this.path(env.media, arguments);
+               },
 
                /**
-                * Deprecated wrapper around {@link LuCI.Poll.start Poll.start()}.
+                * Return the complete URL path to the current view.
                 *
-                * @deprecated
                 * @instance
                 * @memberof LuCI
                 *
-                * @return {boolean}
-                * Returns `true` when the polling loop has been started or `false`
-                * when it was already running.
+                * @return {string}
+                * Returns the URL path to the current view.
                 */
-               run: function() { return Poll.start() },
+               location: function() {
+                       return this.path(env.scriptname, env.requestpath);
+               },
 
 
                /**
-                * @class
+                * Tests whether the passed argument is a JavaScript object.
+                * This function is meant to be an object counterpart to the
+                * standard `Array.isArray()` function.
+                *
+                * @instance
                 * @memberof LuCI
-                * @hideconstructor
-                * @classdesc
                 *
-                * The `dom` class provides convenience method for creating and
-                * manipulating DOM elements.
+                * @param {*} [val]
+                * The value to test
+                *
+                * @return {boolean}
+                * Returns `true` if the given value is of type object and
+                * not `null`, else returns `false`.
                 */
-               dom: Class.singleton(/* @lends LuCI.dom.prototype */ {
-                       __name__: 'LuCI.DOM',
+               isObject: function(val) {
+                       return (val != null && typeof(val) == 'object');
+               },
 
-                       /**
-                        * Tests whether the given argument is a valid DOM `Node`.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} e
-                        * The value to test.
-                        *
-                        * @returns {boolean}
-                        * Returns `true` if the value is a DOM `Node`, else `false`.
-                        */
-                       elem: function(e) {
-                               return (e != null && typeof(e) == 'object' && 'nodeType' in e);
-                       },
+               /**
+                * Return an array of sorted object keys, optionally sorted by
+                * a different key or a different sorting mode.
+                *
+                * @instance
+                * @memberof LuCI
+                *
+                * @param {object} obj
+                * The object to extract the keys from. If the given value is
+                * not an object, the function will return an empty array.
+                *
+                * @param {string} [key]
+                * Specifies the key to order by. This is mainly useful for
+                * nested objects of objects or objects of arrays when sorting
+                * shall not be performed by the primary object keys but by
+                * some other key pointing to a value within the nested values.
+                *
+                * @param {string} [sortmode]
+                * May be either `addr` or `num` to override the natural
+                * lexicographic sorting with a sorting suitable for IP/MAC style
+                * addresses or numeric values respectively.
+                *
+                * @return {string[]}
+                * Returns an array containing the sorted keys of the given object.
+                */
+               sortedKeys: function(obj, key, sortmode) {
+                       if (obj == null || typeof(obj) != 'object')
+                               return [];
 
-                       /**
-                        * Parses a given string as HTML and returns the first child node.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {string} s
-                        * A string containing an HTML fragment to parse. Note that only
-                        * the first result of the resulting structure is returned, so an
-                        * input value of `<div>foo</div> <div>bar</div>` will only return
-                        * the first `div` element node.
-                        *
-                        * @returns {Node}
-                        * Returns the first DOM `Node` extracted from the HTML fragment or
-                        * `null` on parsing failures or if no element could be found.
-                        */
-                       parse: function(s) {
-                               var elem;
+                       return Object.keys(obj).map(function(e) {
+                               var v = (key != null) ? obj[e][key] : e;
 
-                               try {
-                                       domParser = domParser || new DOMParser();
-                                       elem = domParser.parseFromString(s, 'text/html').body.firstChild;
-                               }
-                               catch(e) {}
+                               switch (sortmode) {
+                               case 'addr':
+                                       v = (v != null) ? v.replace(/(?:^|[.:])([0-9a-fA-F]{1,4})/g,
+                                               function(m0, m1) { return ('000' + m1.toLowerCase()).substr(-4) }) : null;
+                                       break;
 
-                               if (!elem) {
-                                       try {
-                                               dummyElem = dummyElem || document.createElement('div');
-                                               dummyElem.innerHTML = s;
-                                               elem = dummyElem.firstChild;
-                                       }
-                                       catch (e) {}
+                               case 'num':
+                                       v = (v != null) ? +v : null;
+                                       break;
                                }
 
-                               return elem || null;
-                       },
+                               return [ e, v ];
+                       }).filter(function(e) {
+                               return (e[1] != null);
+                       }).sort(function(a, b) {
+                               return (a[1] > b[1]);
+                       }).map(function(e) {
+                               return e[0];
+                       });
+               },
 
-                       /**
-                        * Tests whether a given `Node` matches the given query selector.
-                        *
-                        * This function is a convenience wrapper around the standard
-                        * `Node.matches("selector")` function with the added benefit that
-                        * the `node` argument may be a non-`Node` value, in which case
-                        * this function simply returns `false`.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} node
-                        * The `Node` argument to test the selector against.
-                        *
-                        * @param {string} [selector]
-                        * The query selector expression to test against the given node.
-                        *
-                        * @returns {boolean}
-                        * Returns `true` if the given node matches the specified selector
-                        * or `false` when the node argument is no valid DOM `Node` or the
-                        * selector didn't match.
-                        */
-                       matches: function(node, selector) {
-                               var m = this.elem(node) ? node.matches || node.msMatchesSelector : null;
-                               return m ? m.call(node, selector) : false;
-                       },
+               /**
+                * Converts the given value to an array. If the given value is of
+                * type array, it is returned as-is, values of type object are
+                * returned as one-element array containing the object, empty
+                * strings and `null` values are returned as empty array, all other
+                * values are converted using `String()`, trimmed, split on white
+                * space and returned as array.
+                *
+                * @instance
+                * @memberof LuCI
+                *
+                * @param {*} val
+                * The value to convert into an array.
+                *
+                * @return {Array<*>}
+                * Returns the resulting array.
+                */
+               toArray: function(val) {
+                       if (val == null)
+                               return [];
+                       else if (Array.isArray(val))
+                               return val;
+                       else if (typeof(val) == 'object')
+                               return [ val ];
 
-                       /**
-                        * Returns the closest parent node that matches the given query
-                        * selector expression.
-                        *
-                        * This function is a convenience wrapper around the standard
-                        * `Node.closest("selector")` function with the added benefit that
-                        * the `node` argument may be a non-`Node` value, in which case
-                        * this function simply returns `null`.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} node
-                        * The `Node` argument to find the closest parent for.
-                        *
-                        * @param {string} [selector]
-                        * The query selector expression to test against each parent.
-                        *
-                        * @returns {Node|null}
-                        * Returns the closest parent node matching the selector or
-                        * `null` when the node argument is no valid DOM `Node` or the
-                        * selector didn't match any parent.
-                        */
-                       parent: function(node, selector) {
-                               if (this.elem(node) && node.closest)
-                                       return node.closest(selector);
+                       var s = String(val).trim();
 
-                               while (this.elem(node))
-                                       if (this.matches(node, selector))
-                                               return node;
-                                       else
-                                               node = node.parentNode;
+                       if (s == '')
+                               return [];
 
-                               return null;
-                       },
+                       return s.split(/\s+/);
+               },
 
-                       /**
-                        * Appends the given children data to the given node.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} node
-                        * The `Node` argument to append the children to.
-                        *
-                        * @param {*} [children]
-                        * The childrens to append to the given node.
-                        *
-                        * When `children` is an array, then each item of the array
-                        * will be either appended as child element or text node,
-                        * depending on whether the item is a DOM `Node` instance or
-                        * some other non-`null` value. Non-`Node`, non-`null` values
-                        * will be converted to strings first before being passed as
-                        * argument to `createTextNode()`.
-                        *
-                        * When `children` is a function, it will be invoked with
-                        * the passed `node` argument as sole parameter and the `append`
-                        * function will be invoked again, with the given `node` argument
-                        * as first and the return value of the `children` function as
-                        * second parameter.
-                        *
-                        * When `children` is is a DOM `Node` instance, it will be
-                        * appended to the given `node`.
-                        *
-                        * When `children` is any other non-`null` value, it will be
-                        * converted to a string and appened to the `innerHTML` property
-                        * of the given `node`.
-                        *
-                        * @returns {Node|null}
-                        * Returns the last children `Node` appended to the node or `null`
-                        * if either the `node` argument was no valid DOM `node` or if the
-                        * `children` was `null` or didn't result in further DOM nodes.
-                        */
-                       append: function(node, children) {
-                               if (!this.elem(node))
-                                       return null;
+               /**
+                * Returns a promise resolving with either the given value or or with
+                * the given default in case the input value is a rejecting promise.
+                *
+                * @instance
+                * @memberof LuCI
+                *
+                * @param {*} value
+                * The value to resolve the promise with.
+                *
+                * @param {*} defvalue
+                * The default value to resolve the promise with in case the given
+                * input value is a rejecting promise.
+                *
+                * @returns {Promise<*>}
+                * Returns a new promise resolving either to the given input value or
+                * to the given default value on error.
+                */
+               resolveDefault: function(value, defvalue) {
+                       return Promise.resolve(value).catch(function() { return defvalue });
+               },
 
-                               if (Array.isArray(children)) {
-                                       for (var i = 0; i < children.length; i++)
-                                               if (this.elem(children[i]))
-                                                       node.appendChild(children[i]);
-                                               else if (children !== null && children !== undefined)
-                                                       node.appendChild(document.createTextNode('' + children[i]));
+               /**
+                * The request callback function is invoked whenever an HTTP
+                * reply to a request made using the `L.get()`, `L.post()` or
+                * `L.poll()` function is timed out or received successfully.
+                *
+                * @instance
+                * @memberof LuCI
+                *
+                * @callback LuCI.requestCallbackFn
+                * @param {XMLHTTPRequest} xhr
+                * The XMLHTTPRequest instance used to make the request.
+                *
+                * @param {*} data
+                * The response JSON if the response could be parsed as such,
+                * else `null`.
+                *
+                * @param {number} duration
+                * The total duration of the request in milliseconds.
+                */
 
-                                       return node.lastChild;
-                               }
-                               else if (typeof(children) === 'function') {
-                                       return this.append(node, children(node));
-                               }
-                               else if (this.elem(children)) {
-                                       return node.appendChild(children);
-                               }
-                               else if (children !== null && children !== undefined) {
-                                       node.innerHTML = '' + children;
-                                       return node.lastChild;
-                               }
+               /**
+                * Issues a GET request to the given url and invokes the specified
+                * callback function. The function is a wrapper around
+                * {@link LuCI.request#request Request.request()}.
+                *
+                * @deprecated
+                * @instance
+                * @memberof LuCI
+                *
+                * @param {string} url
+                * The URL to request.
+                *
+                * @param {Object<string, string>} [args]
+                * Additional query string arguments to append to the URL.
+                *
+                * @param {LuCI.requestCallbackFn} cb
+                * The callback function to invoke when the request finishes.
+                *
+                * @return {Promise<null>}
+                * Returns a promise resolving to `null` when concluded.
+                */
+               get: function(url, args, cb) {
+                       return this.poll(null, url, args, cb, false);
+               },
 
-                               return null;
-                       },
-
-                       /**
-                        * Replaces the content of the given node with the given children.
-                        *
-                        * This function first removes any children of the given DOM
-                        * `Node` and then adds the given given children following the
-                        * rules outlined below.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} node
-                        * The `Node` argument to replace the children of.
-                        *
-                        * @param {*} [children]
-                        * The childrens to replace into the given node.
-                        *
-                        * When `children` is an array, then each item of the array
-                        * will be either appended as child element or text node,
-                        * depending on whether the item is a DOM `Node` instance or
-                        * some other non-`null` value. Non-`Node`, non-`null` values
-                        * will be converted to strings first before being passed as
-                        * argument to `createTextNode()`.
-                        *
-                        * When `children` is a function, it will be invoked with
-                        * the passed `node` argument as sole parameter and the `append`
-                        * function will be invoked again, with the given `node` argument
-                        * as first and the return value of the `children` function as
-                        * second parameter.
-                        *
-                        * When `children` is is a DOM `Node` instance, it will be
-                        * appended to the given `node`.
-                        *
-                        * When `children` is any other non-`null` value, it will be
-                        * converted to a string and appened to the `innerHTML` property
-                        * of the given `node`.
-                        *
-                        * @returns {Node|null}
-                        * Returns the last children `Node` appended to the node or `null`
-                        * if either the `node` argument was no valid DOM `node` or if the
-                        * `children` was `null` or didn't result in further DOM nodes.
-                        */
-                       content: function(node, children) {
-                               if (!this.elem(node))
-                                       return null;
-
-                               var dataNodes = node.querySelectorAll('[data-idref]');
-
-                               for (var i = 0; i < dataNodes.length; i++)
-                                       delete this.registry[dataNodes[i].getAttribute('data-idref')];
-
-                               while (node.firstChild)
-                                       node.removeChild(node.firstChild);
-
-                               return this.append(node, children);
-                       },
-
-                       /**
-                        * Sets attributes or registers event listeners on element nodes.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} node
-                        * The `Node` argument to set the attributes or add the event
-                        * listeners for. When the given `node` value is not a valid
-                        * DOM `Node`, the function returns and does nothing.
-                        *
-                        * @param {string|Object<string, *>} key
-                        * Specifies either the attribute or event handler name to use,
-                        * or an object containing multiple key, value pairs which are
-                        * each added to the node as either attribute or event handler,
-                        * depending on the respective value.
-                        *
-                        * @param {*} [val]
-                        * Specifies the attribute value or event handler function to add.
-                        * If the `key` parameter is an `Object`, this parameter will be
-                        * ignored.
-                        *
-                        * When `val` is of type function, it will be registered as event
-                        * handler on the given `node` with the `key` parameter being the
-                        * event name.
-                        *
-                        * When `val` is of type object, it will be serialized as JSON and
-                        * added as attribute to the given `node`, using the given `key`
-                        * as attribute name.
-                        *
-                        * When `val` is of any other type, it will be added as attribute
-                        * to the given `node` as-is, with the underlying `setAttribute()`
-                        * call implicitely turning it into a string.
-                        */
-                       attr: function(node, key, val) {
-                               if (!this.elem(node))
-                                       return null;
-
-                               var attr = null;
-
-                               if (typeof(key) === 'object' && key !== null)
-                                       attr = key;
-                               else if (typeof(key) === 'string')
-                                       attr = {}, attr[key] = val;
-
-                               for (key in attr) {
-                                       if (!attr.hasOwnProperty(key) || attr[key] == null)
-                                               continue;
-
-                                       switch (typeof(attr[key])) {
-                                       case 'function':
-                                               node.addEventListener(key, attr[key]);
-                                               break;
-
-                                       case 'object':
-                                               node.setAttribute(key, JSON.stringify(attr[key]));
-                                               break;
-
-                                       default:
-                                               node.setAttribute(key, attr[key]);
-                                       }
-                               }
-                       },
-
-                       /**
-                        * Creates a new DOM `Node` from the given `html`, `attr` and
-                        * `data` parameters.
-                        *
-                        * This function has multiple signatures, it can be either invoked
-                        * in the form `create(html[, attr[, data]])` or in the form
-                        * `create(html[, data])`. The used variant is determined from the
-                        * type of the second argument.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {*} html
-                        * Describes the node to create.
-                        *
-                        * When the value of `html` is of type array, a `DocumentFragment`
-                        * node is created and each item of the array is first converted
-                        * to a DOM `Node` by passing it through `create()` and then added
-                        * as child to the fragment.
-                        *
-                        * When the value of `html` is a DOM `Node` instance, no new
-                        * element will be created but the node will be used as-is.
-                        *
-                        * When the value of `html` is a string starting with `<`, it will
-                        * be passed to `dom.parse()` and the resulting value is used.
-                        *
-                        * When the value of `html` is any other string, it will be passed
-                        * to `document.createElement()` for creating a new DOM `Node` of
-                        * the given name.
-                        *
-                        * @param {Object<string, *>} [attr]
-                        * Specifies an Object of key, value pairs to set as attributes
-                        * or event handlers on the created node. Refer to
-                        * {@link LuCI.dom#attr dom.attr()} for details.
-                        *
-                        * @param {*} [data]
-                        * Specifies children to append to the newly created element.
-                        * Refer to {@link LuCI.dom#append dom.append()} for details.
-                        *
-                        * @throws {InvalidCharacterError}
-                        * Throws an `InvalidCharacterError` when the given `html`
-                        * argument contained malformed markup (such as not escaped
-                        * `&` characters in XHTML mode) or when the given node name
-                        * in `html` contains characters which are not legal in DOM
-                        * element names, such as spaces.
-                        *
-                        * @returns {Node}
-                        * Returns the newly created `Node`.
-                        */
-                       create: function() {
-                               var html = arguments[0],
-                                   attr = arguments[1],
-                                   data = arguments[2],
-                                   elem;
-
-                               if (!(attr instanceof Object) || Array.isArray(attr))
-                                       data = attr, attr = null;
-
-                               if (Array.isArray(html)) {
-                                       elem = document.createDocumentFragment();
-                                       for (var i = 0; i < html.length; i++)
-                                               elem.appendChild(this.create(html[i]));
-                               }
-                               else if (this.elem(html)) {
-                                       elem = html;
-                               }
-                               else if (html.charCodeAt(0) === 60) {
-                                       elem = this.parse(html);
-                               }
-                               else {
-                                       elem = document.createElement(html);
-                               }
-
-                               if (!elem)
-                                       return null;
-
-                               this.attr(elem, attr);
-                               this.append(elem, data);
-
-                               return elem;
-                       },
-
-                       registry: {},
-
-                       /**
-                        * Attaches or detaches arbitrary data to and from a DOM `Node`.
-                        *
-                        * This function is useful to attach non-string values or runtime
-                        * data that is not serializable to DOM nodes. To decouple data
-                        * from the DOM, values are not added directly to nodes, but
-                        * inserted into a registry instead which is then referenced by a
-                        * string key stored as `data-idref` attribute in the node.
-                        *
-                        * This function has multiple signatures and is sensitive to the
-                        * number of arguments passed to it.
-                        *
-                        *  - `dom.data(node)` -
-                        *     Fetches all data associated with the given node.
-                        *  - `dom.data(node, key)` -
-                        *     Fetches a specific key associated with the given node.
-                        *  - `dom.data(node, key, val)` -
-                        *     Sets a specific key to the given value associated with the
-                        *     given node.
-                        *  - `dom.data(node, null)` -
-                        *     Clears any data associated with the node.
-                        *  - `dom.data(node, key, null)` -
-                        *     Clears the given key associated with the node.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {Node} node
-                        * The DOM `Node` instance to set or retrieve the data for.
-                        *
-                        * @param {string|null} [key]
-                        * This is either a string specifying the key to retrieve, or
-                        * `null` to unset the entire node data.
-                        *
-                        * @param {*|null} [val]
-                        * This is either a non-`null` value to set for a given key or
-                        * `null` to remove the given `key` from the specified node.
-                        *
-                        * @returns {*}
-                        * Returns the get or set value, or `null` when no value could
-                        * be found.
-                        */
-                       data: function(node, key, val) {
-                               var id = node.getAttribute('data-idref');
-
-                               /* clear all data */
-                               if (arguments.length > 1 && key == null) {
-                                       if (id != null) {
-                                               node.removeAttribute('data-idref');
-                                               val = this.registry[id]
-                                               delete this.registry[id];
-                                               return val;
-                                       }
-
-                                       return null;
-                               }
-
-                               /* clear a key */
-                               else if (arguments.length > 2 && key != null && val == null) {
-                                       if (id != null) {
-                                               val = this.registry[id][key];
-                                               delete this.registry[id][key];
-                                               return val;
-                                       }
-
-                                       return null;
-                               }
-
-                               /* set a key */
-                               else if (arguments.length > 2 && key != null && val != null) {
-                                       if (id == null) {
-                                               do { id = Math.floor(Math.random() * 0xffffffff).toString(16) }
-                                               while (this.registry.hasOwnProperty(id));
-
-                                               node.setAttribute('data-idref', id);
-                                               this.registry[id] = {};
-                                       }
-
-                                       return (this.registry[id][key] = val);
-                               }
-
-                               /* get all data */
-                               else if (arguments.length == 1) {
-                                       if (id != null)
-                                               return this.registry[id];
-
-                                       return null;
-                               }
-
-                               /* get a key */
-                               else if (arguments.length == 2) {
-                                       if (id != null)
-                                               return this.registry[id][key];
-                               }
-
-                               return null;
-                       },
-
-                       /**
-                        * Binds the given class instance ot the specified DOM `Node`.
-                        *
-                        * This function uses the `dom.data()` facility to attach the
-                        * passed instance of a Class to a node. This is needed for
-                        * complex widget elements or similar where the corresponding
-                        * class instance responsible for the element must be retrieved
-                        * from DOM nodes obtained by `querySelector()` or similar means.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {Node} node
-                        * The DOM `Node` instance to bind the class to.
-                        *
-                        * @param {Class} inst
-                        * The Class instance to bind to the node.
-                        *
-                        * @throws {TypeError}
-                        * Throws a `TypeError` when the given instance argument isn't
-                        * a valid Class instance.
-                        *
-                        * @returns {Class}
-                        * Returns the bound class instance.
-                        */
-                       bindClassInstance: function(node, inst) {
-                               if (!(inst instanceof Class))
-                                       L.error('TypeError', 'Argument must be a class instance');
-
-                               return this.data(node, '_class', inst);
-                       },
-
-                       /**
-                        * Finds a bound class instance on the given node itself or the
-                        * first bound instance on its closest parent node.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {Node} node
-                        * The DOM `Node` instance to start from.
-                        *
-                        * @returns {Class|null}
-                        * Returns the founds class instance if any or `null` if no bound
-                        * class could be found on the node itself or any of its parents.
-                        */
-                       findClassInstance: function(node) {
-                               var inst = null;
-
-                               do {
-                                       inst = this.data(node, '_class');
-                                       node = node.parentNode;
-                               }
-                               while (!(inst instanceof Class) && node != null);
-
-                               return inst;
-                       },
-
-                       /**
-                        * Finds a bound class instance on the given node itself or the
-                        * first bound instance on its closest parent node and invokes
-                        * the specified method name on the found class instance.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {Node} node
-                        * The DOM `Node` instance to start from.
-                        *
-                        * @param {string} method
-                        * The name of the method to invoke on the found class instance.
-                        *
-                        * @param {...*} params
-                        * Additional arguments to pass to the invoked method as-is.
-                        *
-                        * @returns {*|null}
-                        * Returns the return value of the invoked method if a class
-                        * instance and method has been found. Returns `null` if either
-                        * no bound class instance could be found, or if the found
-                        * instance didn't have the requested `method`.
-                        */
-                       callClassMethod: function(node, method /*, ... */) {
-                               var inst = this.findClassInstance(node);
-
-                               if (inst == null || typeof(inst[method]) != 'function')
-                                       return null;
-
-                               return inst[method].apply(inst, inst.varargs(arguments, 2));
-                       },
-
-                       /**
-                        * The ignore callback function is invoked by `isEmpty()` for each
-                        * child node to decide whether to ignore a child node or not.
-                        *
-                        * When this function returns `false`, the node passed to it is
-                        * ignored, else not.
-                        *
-                        * @callback LuCI.dom~ignoreCallbackFn
-                        * @param {Node} node
-                        * The child node to test.
-                        *
-                        * @returns {boolean}
-                        * Boolean indicating whether to ignore the node or not.
-                        */
-
-                       /**
-                        * Tests whether a given DOM `Node` instance is empty or appears
-                        * empty.
-                        *
-                        * Any element child nodes which have the CSS class `hidden` set
-                        * or for which the optionally passed `ignoreFn` callback function
-                        * returns `false` are ignored.
-                        *
-                        * @instance
-                        * @memberof LuCI.dom
-                        * @param {Node} node
-                        * The DOM `Node` instance to test.
-                        *
-                        * @param {LuCI.dom~ignoreCallbackFn} [ignoreFn]
-                        * Specifies an optional function which is invoked for each child
-                        * node to decide whether the child node should be ignored or not.
-                        *
-                        * @returns {boolean}
-                        * Returns `true` if the node does not have any children or if
-                        * any children node either has a `hidden` CSS class or a `false`
-                        * result when testing it using the given `ignoreFn`.
-                        */
-                       isEmpty: function(node, ignoreFn) {
-                               for (var child = node.firstElementChild; child != null; child = child.nextElementSibling)
-                                       if (!child.classList.contains('hidden') && (!ignoreFn || !ignoreFn(child)))
-                                               return false;
-
-                               return true;
-                       }
-               }),
-
-               Poll: Poll,
-               Class: Class,
-               Request: Request,
+               /**
+                * Issues a POST request to the given url and invokes the specified
+                * callback function. The function is a wrapper around
+                * {@link LuCI.request#request Request.request()}. The request is
+                * sent using `application/x-www-form-urlencoded` encoding and will
+                * contain a field `token` with the current value of `LuCI.env.token`
+                * by default.
+                *
+                * @deprecated
+                * @instance
+                * @memberof LuCI
+                *
+                * @param {string} url
+                * The URL to request.
+                *
+                * @param {Object<string, string>} [args]
+                * Additional post arguments to append to the request body.
+                *
+                * @param {LuCI.requestCallbackFn} cb
+                * The callback function to invoke when the request finishes.
+                *
+                * @return {Promise<null>}
+                * Returns a promise resolving to `null` when concluded.
+                */
+               post: function(url, args, cb) {
+                       return this.poll(null, url, args, cb, true);
+               },
 
                /**
-                * @class
+                * Register a polling HTTP request that invokes the specified
+                * callback function. The function is a wrapper around
+                * {@link LuCI.request.poll#add Request.poll.add()}.
+                *
+                * @deprecated
+                * @instance
                 * @memberof LuCI
-                * @hideconstructor
-                * @classdesc
                 *
-                * The `view` class forms the basis of views and provides a standard
-                * set of methods to inherit from.
+                * @param {number} interval
+                * The poll interval to use. If set to a value less than or equal
+                * to `0`, it will default to the global poll interval configured
+                * in `LuCI.env.pollinterval`.
+                *
+                * @param {string} url
+                * The URL to request.
+                *
+                * @param {Object<string, string>} [args]
+                * Specifies additional arguments for the request. For GET requests,
+                * the arguments are appended to the URL as query string, for POST
+                * requests, they'll be added to the request body.
+                *
+                * @param {LuCI.requestCallbackFn} cb
+                * The callback function to invoke whenever a request finishes.
+                *
+                * @param {boolean} [post=false]
+                * When set to `false` or not specified, poll requests will be made
+                * using the GET method. When set to `true`, POST requests will be
+                * issued. In case of POST requests, the request body will contain
+                * an argument `token` with the current value of `LuCI.env.token` by
+                * default, regardless of the parameters specified with `args`.
+                *
+                * @return {function}
+                * Returns the internally created function that has been passed to
+                * {@link LuCI.request.poll#add Request.poll.add()}. This value can
+                * be passed to {@link LuCI.poll.remove Poll.remove()} to remove the
+                * polling request.
                 */
-               view: Class.extend(/* @lends LuCI.view.prototype */ {
-                       __name__: 'LuCI.View',
-
-                       __init__: function() {
-                               var vp = document.getElementById('view');
+               poll: function(interval, url, args, cb, post) {
+                       if (interval !== null && interval <= 0)
+                               interval = env.pollinterval;
 
-                               L.dom.content(vp, E('div', { 'class': 'spinning' }, _('Loading view…')));
+                       var data = post ? { token: env.token } : null,
+                           method = post ? 'POST' : 'GET';
 
-                               return Promise.resolve(this.load())
-                                       .then(L.bind(this.render, this))
-                                       .then(L.bind(function(nodes) {
-                                               var vp = document.getElementById('view');
+                       if (!/^(?:\/|\S+:\/\/)/.test(url))
+                               url = this.url(url);
 
-                                               L.dom.content(vp, nodes);
-                                               L.dom.append(vp, this.addFooter());
-                                       }, this)).catch(L.error);
-                       },
+                       if (args != null)
+                               data = Object.assign(data || {}, args);
 
-                       /**
-                        * The load function is invoked before the view is rendered.
-                        *
-                        * The invocation of this function is wrapped by
-                        * `Promise.resolve()` so it may return Promises if needed.
-                        *
-                        * The return value of the function (or the resolved values
-                        * of the promise returned by it) will be passed as first
-                        * argument to `render()`.
-                        *
-                        * This function is supposed to be overwritten by subclasses,
-                        * the default implementation does nothing.
-                        *
-                        * @instance
-                        * @abstract
-                        * @memberof LuCI.view
-                        *
-                        * @returns {*|Promise<*>}
-                        * May return any value or a Promise resolving to any value.
-                        */
-                       load: function() {},
+                       if (interval !== null)
+                               return Request.poll.add(interval, url, { method: method, query: data }, cb);
+                       else
+                               return Request.request(url, { method: method, query: data })
+                                       .then(function(res) {
+                                               var json = null;
+                                               if (/^application\/json\b/.test(res.headers.get('Content-Type')))
+                                                       try { json = res.json() } catch(e) {}
+                                               cb(res.xhr, json, res.duration);
+                                       });
+               },
 
-                       /**
-                        * The render function is invoked after the
-                        * {@link LuCI.view#load load()} function and responsible
-                        * for setting up the view contents. It must return a DOM
-                        * `Node` or `DocumentFragment` holding the contents to
-                        * insert into the view area.
-                        *
-                        * The invocation of this function is wrapped by
-                        * `Promise.resolve()` so it may return Promises if needed.
-                        *
-                        * The return value of the function (or the resolved values
-                        * of the promise returned by it) will be inserted into the
-                        * main content area using
-                        * {@link LuCI.dom#append dom.append()}.
-                        *
-                        * This function is supposed to be overwritten by subclasses,
-                        * the default implementation does nothing.
-                        *
-                        * @instance
-                        * @abstract
-                        * @memberof LuCI.view
-                        * @param {*|null} load_results
-                        * This function will receive the return value of the
-                        * {@link LuCI.view#load view.load()} function as first
-                        * argument.
-                        *
-                        * @returns {Node|Promise<Node>}
-                        * Should return a DOM `Node` value or a `Promise` resolving
-                        * to a `Node` value.
-                        */
-                       render: function() {},
+               /**
+                * Check whether a view has sufficient permissions.
+                *
+                * @return {boolean|null}
+                * Returns `null` if the current session has no permission at all to
+                * load resources required by the view. Returns `false` if readonly
+                * permissions are granted or `true` if at least one required ACL
+                * group is granted with write permissions.
+                */
+               hasViewPermission: function() {
+                       if (!this.isObject(env.nodespec) || !env.nodespec.satisfied)
+                           return null;
 
-                       /**
-                        * The handleSave function is invoked when the user clicks
-                        * the `Save` button in the page action footer.
-                        *
-                        * The default implementation should be sufficient for most
-                        * views using {@link form#Map form.Map()} based forms - it
-                        * will iterate all forms present in the view and invoke
-                        * the {@link form#Map#save Map.save()} method on each form.
-                        *
-                        * Views not using `Map` instances or requiring other special
-                        * logic should overwrite `handleSave()` with a custom
-                        * implementation.
-                        *
-                        * To disable the `Save` page footer button, views extending
-                        * this base class should overwrite the `handleSave` function
-                        * with `null`.
-                        *
-                        * The invocation of this function is wrapped by
-                        * `Promise.resolve()` so it may return Promises if needed.
-                        *
-                        * @instance
-                        * @memberof LuCI.view
-                        * @param {Event} ev
-                        * The DOM event that triggered the function.
-                        *
-                        * @returns {*|Promise<*>}
-                        * Any return values of this function are discarded, but
-                        * passed through `Promise.resolve()` to ensure that any
-                        * returned promise runs to completion before the button
-                        * is reenabled.
-                        */
-                       handleSave: function(ev) {
-                               var tasks = [];
+                       return !env.nodespec.readonly;
+               },
 
-                               document.getElementById('maincontent')
-                                       .querySelectorAll('.cbi-map').forEach(function(map) {
-                                               tasks.push(L.dom.callClassMethod(map, 'save'));
-                                       });
+               /**
+                * Deprecated wrapper around {@link LuCI.poll.remove Poll.remove()}.
+                *
+                * @deprecated
+                * @instance
+                * @memberof LuCI
+                *
+                * @param {function} entry
+                * The polling function to remove.
+                *
+                * @return {boolean}
+                * Returns `true` when the function has been removed or `false` if
+                * it could not be found.
+                */
+               stop: function(entry) { return Poll.remove(entry) },
 
-                               return Promise.all(tasks);
-                       },
+               /**
+                * Deprecated wrapper around {@link LuCI.poll.stop Poll.stop()}.
+                *
+                * @deprecated
+                * @instance
+                * @memberof LuCI
+                *
+                * @return {boolean}
+                * Returns `true` when the polling loop has been stopped or `false`
+                * when it didn't run to begin with.
+                */
+               halt: function() { return Poll.stop() },
 
-                       /**
-                        * The handleSaveApply function is invoked when the user clicks
-                        * the `Save & Apply` button in the page action footer.
-                        *
-                        * The default implementation should be sufficient for most
-                        * views using {@link form#Map form.Map()} based forms - it
-                        * will first invoke
-                        * {@link LuCI.view.handleSave view.handleSave()} and then
-                        * call {@link ui#changes#apply ui.changes.apply()} to start the
-                        * modal config apply and page reload flow.
-                        *
-                        * Views not using `Map` instances or requiring other special
-                        * logic should overwrite `handleSaveApply()` with a custom
-                        * implementation.
-                        *
-                        * To disable the `Save & Apply` page footer button, views
-                        * extending this base class should overwrite the
-                        * `handleSaveApply` function with `null`.
-                        *
-                        * The invocation of this function is wrapped by
-                        * `Promise.resolve()` so it may return Promises if needed.
-                        *
-                        * @instance
-                        * @memberof LuCI.view
-                        * @param {Event} ev
-                        * The DOM event that triggered the function.
-                        *
-                        * @returns {*|Promise<*>}
-                        * Any return values of this function are discarded, but
-                        * passed through `Promise.resolve()` to ensure that any
-                        * returned promise runs to completion before the button
-                        * is reenabled.
-                        */
-                       handleSaveApply: function(ev, mode) {
-                               return this.handleSave(ev).then(function() {
-                                       L.ui.changes.apply(mode == '0');
-                               });
-                       },
+               /**
+                * Deprecated wrapper around {@link LuCI.poll.start Poll.start()}.
+                *
+                * @deprecated
+                * @instance
+                * @memberof LuCI
+                *
+                * @return {boolean}
+                * Returns `true` when the polling loop has been started or `false`
+                * when it was already running.
+                */
+               run: function() { return Poll.start() },
 
-                       /**
-                        * The handleReset function is invoked when the user clicks
-                        * the `Reset` button in the page action footer.
-                        *
-                        * The default implementation should be sufficient for most
-                        * views using {@link form#Map form.Map()} based forms - it
-                        * will iterate all forms present in the view and invoke
-                        * the {@link form#Map#save Map.reset()} method on each form.
-                        *
-                        * Views not using `Map` instances or requiring other special
-                        * logic should overwrite `handleReset()` with a custom
-                        * implementation.
-                        *
-                        * To disable the `Reset` page footer button, views extending
-                        * this base class should overwrite the `handleReset` function
-                        * with `null`.
-                        *
-                        * The invocation of this function is wrapped by
-                        * `Promise.resolve()` so it may return Promises if needed.
-                        *
-                        * @instance
-                        * @memberof LuCI.view
-                        * @param {Event} ev
-                        * The DOM event that triggered the function.
-                        *
-                        * @returns {*|Promise<*>}
-                        * Any return values of this function are discarded, but
-                        * passed through `Promise.resolve()` to ensure that any
-                        * returned promise runs to completion before the button
-                        * is reenabled.
-                        */
-                       handleReset: function(ev) {
-                               var tasks = [];
+               /**
+                * Legacy `L.dom` class alias. New view code should use `'require dom';`
+                * to request the `LuCI.dom` class.
+                *
+                * @instance
+                * @memberof LuCI
+                * @deprecated
+                */
+               dom: DOM,
 
-                               document.getElementById('maincontent')
-                                       .querySelectorAll('.cbi-map').forEach(function(map) {
-                                               tasks.push(L.dom.callClassMethod(map, 'reset'));
-                                       });
+               /**
+                * Legacy `L.view` class alias. New view code should use `'require view';`
+                * to request the `LuCI.view` class.
+                *
+                * @instance
+                * @memberof LuCI
+                * @deprecated
+                */
+               view: View,
 
-                               return Promise.all(tasks);
-                       },
+               /**
+                * Legacy `L.Poll` class alias. New view code should use `'require poll';`
+                * to request the `LuCI.poll` class.
+                *
+                * @instance
+                * @memberof LuCI
+                * @deprecated
+                */
+               Poll: Poll,
 
-                       /**
-                        * Renders a standard page action footer if any of the
-                        * `handleSave()`, `handleSaveApply()` or `handleReset()`
-                        * functions are defined.
-                        *
-                        * The default implementation should be sufficient for most
-                        * views - it will render a standard page footer with action
-                        * buttons labeled `Save`, `Save & Apply` and `Reset`
-                        * triggering the `handleSave()`, `handleSaveApply()` and
-                        * `handleReset()` functions respectively.
-                        *
-                        * When any of these `handle*()` functions is overwritten
-                        * with `null` by a view extending this class, the
-                        * corresponding button will not be rendered.
-                        *
-                        * @instance
-                        * @memberof LuCI.view
-                        * @returns {DocumentFragment}
-                        * Returns a `DocumentFragment` containing the footer bar
-                        * with buttons for each corresponding `handle*()` action
-                        * or an empty `DocumentFragment` if all three `handle*()`
-                        * methods are overwritten with `null`.
-                        */
-                       addFooter: function() {
-                               var footer = E([]);
-
-                               var saveApplyBtn = this.handleSaveApply ? new L.ui.ComboButton('0', {
-                                       0: [ _('Save & Apply') ],
-                                       1: [ _('Apply unchecked') ]
-                               }, {
-                                       classes: {
-                                               0: 'cbi-button cbi-button-apply important',
-                                               1: 'cbi-button cbi-button-negative important'
-                                       },
-                                       click: L.ui.createHandlerFn(this, 'handleSaveApply')
-                               }).render() : E([]);
-
-                               if (this.handleSaveApply || this.handleSave || this.handleReset) {
-                                       footer.appendChild(E('div', { 'class': 'cbi-page-actions' }, [
-                                               saveApplyBtn, ' ',
-                                               this.handleSave ? E('button', {
-                                                       'class': 'cbi-button cbi-button-save',
-                                                       'click': L.ui.createHandlerFn(this, 'handleSave')
-                                               }, [ _('Save') ]) : '', ' ',
-                                               this.handleReset ? E('button', {
-                                                       'class': 'cbi-button cbi-button-reset',
-                                                       'click': L.ui.createHandlerFn(this, 'handleReset')
-                                               }, [ _('Reset') ]) : ''
-                                       ]));
-                               }
+               /**
+                * Legacy `L.Request` class alias. New view code should use `'require request';`
+                * to request the `LuCI.request` class.
+                *
+                * @instance
+                * @memberof LuCI
+                * @deprecated
+                */
+               Request: Request,
 
-                               return footer;
-                       }
-               })
+               /**
+                * Legacy `L.Class` class alias. New view code should use `'require baseclass';`
+                * to request the `LuCI.baseclass` class.
+                *
+                * @instance
+                * @memberof LuCI
+                * @deprecated
+                */
+               Class: Class
        });
 
        /**
-        * @class
+        * @class xhr
         * @memberof LuCI
         * @deprecated
         * @classdesc
         *
-        * The `LuCI.XHR` class is a legacy compatibility shim for the
+        * The `LuCI.xhr` class is a legacy compatibility shim for the
         * functionality formerly provided by `xhr.js`. It is registered as global
         * `window.XHR` symbol for compatibility with legacy code.
         *
-        * New code should use {@link LuCI.Request} instead to implement HTTP
+        * New code should use {@link LuCI.request} instead to implement HTTP
         * request handling.
         */
-       var XHR = Class.extend(/** @lends LuCI.XHR.prototype */ {
-               __name__: 'LuCI.XHR',
+       var XHR = Class.extend(/** @lends LuCI.xhr.prototype */ {
+               __name__: 'LuCI.xhr',
                __init__: function() {
                        if (window.console && console.debug)
                                console.debug('Direct use XHR() is deprecated, please use L.Request instead');
                 *
                 * @instance
                 * @deprecated
-                * @memberof LuCI.XHR
+                * @memberof LuCI.xhr
                 *
                 * @param {string} url
                 * The URL to request
                 */
                get: function(url, data, callback, timeout) {
                        this.active = true;
-                       L.get(url, data, this._response.bind(this, callback), timeout);
+                       LuCI.prototype.get(url, data, this._response.bind(this, callback), timeout);
                },
 
                /**
                 *
                 * @instance
                 * @deprecated
-                * @memberof LuCI.XHR
+                * @memberof LuCI.xhr
                 *
                 * @param {string} url
                 * The URL to request
                 */
                post: function(url, data, callback, timeout) {
                        this.active = true;
-                       L.post(url, data, this._response.bind(this, callback), timeout);
+                       LuCI.prototype.post(url, data, this._response.bind(this, callback), timeout);
                },
 
                /**
                 *
                 * @instance
                 * @deprecated
-                * @memberof LuCI.XHR
+                * @memberof LuCI.xhr
                 */
                cancel: function() { delete this.active },
 
                 *
                 * @instance
                 * @deprecated
-                * @memberof LuCI.XHR
+                * @memberof LuCI.xhr
                 *
                 * @returns {boolean}
                 * Returns `true` if the request is still running or `false` if it
                 *
                 * @instance
                 * @deprecated
-                * @memberof LuCI.XHR
+                * @memberof LuCI.xhr
                 */
                abort: function() {},
 
                 *
                 * @instance
                 * @deprecated
-                * @memberof LuCI.XHR
+                * @memberof LuCI.xhr
                 *
                 * @throws {InternalError}
                 * Throws an `InternalError` with the message `Not implemented`
                 * when invoked.
                 */
-               send_form: function() { L.error('InternalError', 'Not implemented') },
+               send_form: function() { LuCI.prototype.error('InternalError', 'Not implemented') },
        });
 
-       XHR.get = function() { return window.L.get.apply(window.L, arguments) };
-       XHR.post = function() { return window.L.post.apply(window.L, arguments) };
-       XHR.poll = function() { return window.L.poll.apply(window.L, arguments) };
+       XHR.get = function() { return LuCI.prototype.get.apply(LuCI.prototype, arguments) };
+       XHR.post = function() { return LuCI.prototype.post.apply(LuCI.prototype, arguments) };
+       XHR.poll = function() { return LuCI.prototype.poll.apply(LuCI.prototype, arguments) };
        XHR.stop = Request.poll.remove.bind(Request.poll);
        XHR.halt = Request.poll.stop.bind(Request.poll);
        XHR.run = Request.poll.start.bind(Request.poll);