--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/js/libs/lazyload.js Mon Nov 28 12:11:36 2011 +0100
@@ -0,0 +1,391 @@
+/*jslint browser: true, eqeqeq: true, bitwise: true, newcap: true, immed: true, regexp: false */
+
+/**
+LazyLoad makes it easy and painless to lazily load one or more external
+JavaScript or CSS files on demand either during or after the rendering of a web
+page.
+
+Supported browsers include Firefox 2+, IE6+, Safari 3+ (including Mobile
+Safari), Google Chrome, and Opera 9+. Other browsers may or may not work and
+are not officially supported.
+
+Visit https://github.com/rgrove/lazyload/ for more info.
+
+Copyright (c) 2011 Ryan Grove <ryan@wonko.com>
+All rights reserved.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the 'Software'), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+@module lazyload
+@class LazyLoad
+@static
+@version 2.0.3 (git)
+*/
+
+LazyLoad = (function (doc) {
+ // -- Private Variables ------------------------------------------------------
+
+ // User agent and feature test information.
+ var env,
+
+ // Reference to the <head> element (populated lazily).
+ head,
+
+ // Requests currently in progress, if any.
+ pending = {},
+
+ // Number of times we've polled to check whether a pending stylesheet has
+ // finished loading. If this gets too high, we're probably stalled.
+ pollCount = 0,
+
+ // Queued requests.
+ queue = {css: [], js: []},
+
+ // Reference to the browser's list of stylesheets.
+ styleSheets = doc.styleSheets;
+
+ // -- Private Methods --------------------------------------------------------
+
+ /**
+ Creates and returns an HTML element with the specified name and attributes.
+
+ @method createNode
+ @param {String} name element name
+ @param {Object} attrs name/value mapping of element attributes
+ @return {HTMLElement}
+ @private
+ */
+ function createNode(name, attrs) {
+ var node = doc.createElement(name), attr;
+
+ for (attr in attrs) {
+ if (attrs.hasOwnProperty(attr)) {
+ node.setAttribute(attr, attrs[attr]);
+ }
+ }
+
+ return node;
+ }
+
+ /**
+ Called when the current pending resource of the specified type has finished
+ loading. Executes the associated callback (if any) and loads the next
+ resource in the queue.
+
+ @method finish
+ @param {String} type resource type ('css' or 'js')
+ @private
+ */
+ function finish(type) {
+ var p = pending[type],
+ callback,
+ urls;
+
+ if (p) {
+ callback = p.callback;
+ urls = p.urls;
+
+ urls.shift();
+ pollCount = 0;
+
+ // If this is the last of the pending URLs, execute the callback and
+ // start the next request in the queue (if any).
+ if (!urls.length) {
+ callback && callback.call(p.context, p.obj);
+ pending[type] = null;
+ queue[type].length && load(type);
+ }
+ }
+ }
+
+ /**
+ Populates the <code>env</code> variable with user agent and feature test
+ information.
+
+ @method getEnv
+ @private
+ */
+ function getEnv() {
+ var ua = navigator.userAgent;
+
+ env = {
+ // True if this browser supports disabling async mode on dynamically
+ // created script nodes. See
+ // http://wiki.whatwg.org/wiki/Dynamic_Script_Execution_Order
+ async: doc.createElement('script').async === true
+ };
+
+ (env.webkit = /AppleWebKit\//.test(ua))
+ || (env.ie = /MSIE/.test(ua))
+ || (env.opera = /Opera/.test(ua))
+ || (env.gecko = /Gecko\//.test(ua))
+ || (env.unknown = true);
+ }
+
+ /**
+ Loads the specified resources, or the next resource of the specified type
+ in the queue if no resources are specified. If a resource of the specified
+ type is already being loaded, the new request will be queued until the
+ first request has been finished.
+
+ When an array of resource URLs is specified, those URLs will be loaded in
+ parallel if it is possible to do so while preserving execution order. All
+ browsers support parallel loading of CSS, but only Firefox and Opera
+ support parallel loading of scripts. In other browsers, scripts will be
+ queued and loaded one at a time to ensure correct execution order.
+
+ @method load
+ @param {String} type resource type ('css' or 'js')
+ @param {String|Array} urls (optional) URL or array of URLs to load
+ @param {Function} callback (optional) callback function to execute when the
+ resource is loaded
+ @param {Object} obj (optional) object to pass to the callback function
+ @param {Object} context (optional) if provided, the callback function will
+ be executed in this object's context
+ @private
+ */
+ function load(type, urls, callback, obj, context) {
+ var _finish = function () { finish(type); },
+ isCSS = type === 'css',
+ nodes = [],
+ i, len, node, p, pendingUrls, url;
+
+ env || getEnv();
+
+ if (urls) {
+ // If urls is a string, wrap it in an array. Otherwise assume it's an
+ // array and create a copy of it so modifications won't be made to the
+ // original.
+ urls = typeof urls === 'string' ? [urls] : urls.concat();
+
+ // Create a request object for each URL. If multiple URLs are specified,
+ // the callback will only be executed after all URLs have been loaded.
+ //
+ // Sadly, Firefox and Opera are the only browsers capable of loading
+ // scripts in parallel while preserving execution order. In all other
+ // browsers, scripts must be loaded sequentially.
+ //
+ // All browsers respect CSS specificity based on the order of the link
+ // elements in the DOM, regardless of the order in which the stylesheets
+ // are actually downloaded.
+ if (isCSS || env.async || env.gecko || env.opera) {
+ // Load in parallel.
+ queue[type].push({
+ urls : urls,
+ callback: callback,
+ obj : obj,
+ context : context
+ });
+ } else {
+ // Load sequentially.
+ for (i = 0, len = urls.length; i < len; ++i) {
+ queue[type].push({
+ urls : [urls[i]],
+ callback: i === len - 1 ? callback : null, // callback is only added to the last URL
+ obj : obj,
+ context : context
+ });
+ }
+ }
+ }
+
+ // If a previous load request of this type is currently in progress, we'll
+ // wait our turn. Otherwise, grab the next item in the queue.
+ if (pending[type] || !(p = pending[type] = queue[type].shift())) {
+ return;
+ }
+
+ head || (head = doc.head || doc.getElementsByTagName('head')[0]);
+ pendingUrls = p.urls;
+
+ for (i = 0, len = pendingUrls.length; i < len; ++i) {
+ url = pendingUrls[i];
+
+ if (isCSS) {
+ node = env.gecko ? createNode('style') : createNode('link', {
+ href: url,
+ rel : 'stylesheet'
+ });
+ } else {
+ node = createNode('script', {src: url});
+ node.async = false;
+ }
+
+ node.className = 'lazyload';
+ node.setAttribute('charset', 'utf-8');
+
+ if (env.ie && !isCSS) {
+ node.onreadystatechange = function () {
+ if (/loaded|complete/.test(node.readyState)) {
+ node.onreadystatechange = null;
+ _finish();
+ }
+ };
+ } else if (isCSS && (env.gecko || env.webkit)) {
+ // Gecko and WebKit don't support the onload event on link nodes.
+ if (env.webkit) {
+ // In WebKit, we can poll for changes to document.styleSheets to
+ // figure out when stylesheets have loaded.
+ p.urls[i] = node.href; // resolve relative URLs (or polling won't work)
+ pollWebKit();
+ } else {
+ // In Gecko, we can import the requested URL into a <style> node and
+ // poll for the existence of node.sheet.cssRules. Props to Zach
+ // Leatherman for calling my attention to this technique.
+ node.innerHTML = '@import "' + url + '";';
+ pollGecko(node);
+ }
+ } else {
+ node.onload = node.onerror = _finish;
+ }
+
+ nodes.push(node);
+ }
+
+ for (i = 0, len = nodes.length; i < len; ++i) {
+ head.appendChild(nodes[i]);
+ }
+ }
+
+ /**
+ Begins polling to determine when the specified stylesheet has finished loading
+ in Gecko. Polling stops when all pending stylesheets have loaded or after 10
+ seconds (to prevent stalls).
+
+ Thanks to Zach Leatherman for calling my attention to the @import-based
+ cross-domain technique used here, and to Oleg Slobodskoi for an earlier
+ same-domain implementation. See Zach's blog for more details:
+ http://www.zachleat.com/web/2010/07/29/load-css-dynamically/
+
+ @method pollGecko
+ @param {HTMLElement} node Style node to poll.
+ @private
+ */
+ function pollGecko(node) {
+ var hasRules;
+
+ try {
+ // We don't really need to store this value or ever refer to it again, but
+ // if we don't store it, Closure Compiler assumes the code is useless and
+ // removes it.
+ hasRules = !!node.sheet.cssRules;
+ } catch (ex) {
+ // An exception means the stylesheet is still loading.
+ pollCount += 1;
+
+ if (pollCount < 200) {
+ setTimeout(function () { pollGecko(node); }, 50);
+ } else {
+ // We've been polling for 10 seconds and nothing's happened. Stop
+ // polling and finish the pending requests to avoid blocking further
+ // requests.
+ hasRules && finish('css');
+ }
+
+ return;
+ }
+
+ // If we get here, the stylesheet has loaded.
+ finish('css');
+ }
+
+ /**
+ Begins polling to determine when pending stylesheets have finished loading
+ in WebKit. Polling stops when all pending stylesheets have loaded or after 10
+ seconds (to prevent stalls).
+
+ @method pollWebKit
+ @private
+ */
+ function pollWebKit() {
+ var css = pending.css, i;
+
+ if (css) {
+ i = styleSheets.length;
+
+ // Look for a stylesheet matching the pending URL.
+ while (--i >= 0) {
+ if (styleSheets[i].href === css.urls[0]) {
+ finish('css');
+ break;
+ }
+ }
+
+ pollCount += 1;
+
+ if (css) {
+ if (pollCount < 200) {
+ setTimeout(pollWebKit, 50);
+ } else {
+ // We've been polling for 10 seconds and nothing's happened, which may
+ // indicate that the stylesheet has been removed from the document
+ // before it had a chance to load. Stop polling and finish the pending
+ // request to prevent blocking further requests.
+ finish('css');
+ }
+ }
+ }
+ }
+
+ return {
+
+ /**
+ Requests the specified CSS URL or URLs and executes the specified
+ callback (if any) when they have finished loading. If an array of URLs is
+ specified, the stylesheets will be loaded in parallel and the callback
+ will be executed after all stylesheets have finished loading.
+
+ @method css
+ @param {String|Array} urls CSS URL or array of CSS URLs to load
+ @param {Function} callback (optional) callback function to execute when
+ the specified stylesheets are loaded
+ @param {Object} obj (optional) object to pass to the callback function
+ @param {Object} context (optional) if provided, the callback function
+ will be executed in this object's context
+ @static
+ */
+ css: function (urls, callback, obj, context) {
+ load('css', urls, callback, obj, context);
+ },
+
+ /**
+ Requests the specified JavaScript URL or URLs and executes the specified
+ callback (if any) when they have finished loading. If an array of URLs is
+ specified and the browser supports it, the scripts will be loaded in
+ parallel and the callback will be executed after all scripts have
+ finished loading.
+
+ Currently, only Firefox and Opera support parallel loading of scripts while
+ preserving execution order. In other browsers, scripts will be
+ queued and loaded one at a time to ensure correct execution order.
+
+ @method js
+ @param {String|Array} urls JS URL or array of JS URLs to load
+ @param {Function} callback (optional) callback function to execute when
+ the specified scripts are loaded
+ @param {Object} obj (optional) object to pass to the callback function
+ @param {Object} context (optional) if provided, the callback function
+ will be executed in this object's context
+ @static
+ */
+ js: function (urls, callback, obj, context) {
+ load('js', urls, callback, obj, context);
+ }
+
+ };
+})(this.document);