[third] Add Lazyload.js

This is a small, MIT-licensed lib from https://github.com/rgrove/lazyload

(imported from commit c6e43c06dfe3fa8559b2a3d28a48d9e0a6848283)

static/third/lazyload/HISTORY

@@ -0,0 +1,68 @@
+LazyLoad Changelog
+================================================================================
+
+Version 2.0.3 (2011-07-05)
+  * Fixed a bug caused by an unwanted Closure Compiler optimization that broke
+    CSS load completion detection in Gecko when using the minified version of
+    LazyLoad. [Allex Wang]
+  * Fixed a race condition in which a URL could be removed from the "pending"
+    queue if it finished loading before other URLs in the same batch had been
+    added to the queue, resulting in the queue's length changing unexpectedly
+    during iteration. [Klaas Neirinck]
+
+Version 2.0.2 (2011-04-17)
+  * Added support for reliable detection of CSS load completion in Gecko
+    browsers based on a technique described by Zach Leatherman at
+    <http://www.zachleat.com/web/2010/07/29/load-css-dynamically/>.
+  * Fixed a bug that prevented CSS load completion from being detected in WebKit
+    when there were no other stylesheets on the page. [Klaas Neirinck]
+  * Fixed a bug that could prevent CSS callbacks from being called in IE.
+
+Version 2.0.1 (2011-03-05)
+  * Added support for async=false. This ensures that parallel script loading
+    still works in Firefox 4 while preserving execution order. For more info,
+    see <http://wiki.whatwg.org/wiki/Dynamic_Script_Execution_Order>.
+  * Stylesheet load completion is now detected reliably in WebKit by polling
+    document.styleSheets for changes. Thanks to Jonathan Cook for suggesting
+    this solution.
+  * Dynamically created script and link nodes are now given a "lazyload" class
+    so they can be identified later.
+  * The charset for dynamically created script and link nodes is set to "utf-8".
+
+Version 2.0.0 (2009-08-06)
+  * Added support for CSS. Caveat: Gecko and WebKit don't support the onload
+    event for link nodes, so the CSS callback will fire almost immediately in
+    those browsers.
+  * When an array of URLs is specified, the resources will be loaded in parallel
+    in browsers that support it. Currently, all browsers support loading CSS in
+    parallel, but only Gecko and Opera support parallel scripts while preserving
+    execution order. 
+  * The load() method has been replaced by css() and js() methods for loading
+    CSS and JS, respectively.
+  * The loadOnce() method has been removed, since it wasn't terribly useful.
+  * Improved reliability in all supported browsers.
+
+Version 1.0.4 (2008-07-24)
+  * Improved reliability with all supported browsers.
+  * Reduced the minified size to 1751 bytes (a whopping 67 bytes smaller than
+    version 1.0.3).
+  * Fixed a bug that caused the load completion callback to fire immediately in
+    Safari 3.x.
+  * Fixed a bug that caused the load completion callback to fail to fire in
+    Internet Explorer if the script was loaded from the cache.
+
+Version 1.0.3 (2007-06-18)
+  * Added "force" parameter to the loadOnce() method to force execution of the
+    callback even when all specified scripts have already been loaded.
+
+Version 1.0.2 (2007-06-02)
+  * Improved browser detection.
+  * Switched to NaturalDocs for source documentation.
+
+Version 1.0.1 (2007-05-30)
+  * Fixed potential race condition when load() is called multiple times in
+    succession.
+  * Refactored to reduce complexity.
+
+Version 1.0.0 (2007-05-29)
+  * First release.

static/third/lazyload/LICENSE

@@ -0,0 +1,19 @@
+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.

static/third/lazyload/README.md

@@ -0,0 +1,97 @@
+LazyLoad
+========
+
+LazyLoad is a tiny (only 966 bytes minified and gzipped), dependency-free
+JavaScript utility that makes it super easy to load external JavaScript and CSS
+files on demand.
+
+Whenever possible, LazyLoad will automatically load resources in parallel while
+ensuring execution order when you specify an array of URLs to load. In browsers
+that don't preserve the execution order of asynchronously-loaded scripts,
+LazyLoad will safely load the scripts sequentially.
+
+Use LazyLoad when you need a small, fast, safe dynamic JS or CSS loader, but
+don't need the overhead of dependency management or other extra functionality
+that larger script loaders provide.
+
+Downloads
+---------
+
+  * [lazyload.js](https://github.com/rgrove/lazyload/raw/master/lazyload.js) (full source)
+
+Usage
+-----
+
+Using LazyLoad is simple. Just call the appropriate method -- `css()` to load
+CSS, `js()` to load JavaScript -- and pass in a URL or array of URLs to load.
+You can also provide a callback function if you'd like to be notified when the
+resources have finished loading, as well as an argument to pass to the callback
+and a context in which to execute the callback.
+
+```js
+// Load a single JavaScript file and execute a callback when it finishes.
+LazyLoad.js('http://example.com/foo.js', function () {
+  alert('foo.js has been loaded');
+});
+
+// Load multiple JS files and execute a callback when they've all finished.
+LazyLoad.js(['foo.js', 'bar.js', 'baz.js'], function () {
+  alert('all files have been loaded');
+});
+
+// Load a CSS file and pass an argument to the callback function.
+LazyLoad.css('foo.css', function (arg) {
+  alert(arg);
+}, 'foo.css has been loaded');
+
+// Load a CSS file and execute the callback in a different scope.
+LazyLoad.css('foo.css', function () {
+  alert(this.foo); // displays 'bar'
+}, null, {foo: 'bar'});
+```
+
+Supported Browsers
+------------------
+
+  * Firefox 2+
+  * Google Chrome
+  * Internet Explorer 6+
+  * Opera 9+
+  * Safari 3+
+  * Mobile Safari
+  * Android
+
+Other browsers may work, but haven't been tested. It's a safe bet that anything
+based on a recent version of Gecko or WebKit will probably work.
+
+Caveats
+-------
+
+All browsers support parallel loading of CSS. However, only Firefox and Opera
+currently support parallel script loading while preserving execution order. To
+ensure that scripts are always executed in the correct order, LazyLoad will load
+all scripts sequentially in browsers other than Firefox and Opera. Hopefully
+other browsers will improve their parallel script loading behavior soon.
+
+License
+-------
+
+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.

static/third/lazyload/lazyload.js

@@ -0,0 +1,390 @@
+/*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
+*/
+
+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|Trident/.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 && 'onreadystatechange' in node && !('draggable' in node)) {
+        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);

tools/jslint/check-all.js

@@ -3,7 +3,8 @@
 // Global variables, categorized by place of definition.
 var globals =
     // Third-party libraries
-      ' $ _ jQuery Spinner Handlebars XDate zxcvbn Intl mixpanel Notification Dropbox'
+      ' $ _ jQuery Spinner Handlebars XDate zxcvbn Intl mixpanel Notification'
+    + ' LazyLoad Dropbox'
 
     // Node-based unit tests
     + ' module'

zproject/settings.py

@@ -356,6 +356,7 @@ JS_SPECS = {
             'third/jquery-throttle-debounce/jquery.ba-throttle-debounce.js',
             'third/jquery-idle/jquery.idle.js',
             'third/jquery-autosize/jquery.autosize.js',
+            'third/lazyload/lazyload.js',
             'third/spectrum/spectrum.js',
             ('third/handlebars/handlebars.runtime.js'
                 if PIPELINE