New library for loading 3rd party javascript APIs

source/js/VMM.LoadLib.js

@@ -0,0 +1,251 @@
+/*
+	LoadLib
+	Based on LazyLoad by Ryan Grove
+	https://github.com/rgrove/lazyload/ 
+	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.
+
+================================================== */
+
+
+
+if(typeof VMM != 'undefined' && typeof VMM.LoadLib == 'undefined') {
+	//VMM.LoadLib.js('http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js', onJQueryLoaded);
+	//VMM.LoadLib.css('http://someurl.css', onCSSLoaded);
+	
+
+	
+	VMM.LoadLib = (function (doc) {
+		var env,
+		head,
+		pending = {},
+		pollCount = 0,
+		queue = {css: [], js: []},
+		styleSheets = doc.styleSheets;
+	
+		var loaded_Array = [];
+	
+		function isLoaded(url) {
+			
+			for(var i=0; i<loaded_Array.length; i++) {
+				var has_been_loaded = false;
+				if (loaded_Array[i] == url) {
+					has_been_loaded = true;
+				}
+				
+				if (!has_been_loaded) {
+					loaded_Array.push(url);
+				}
+				
+				return has_been_loaded;
+			}
+			
+		}
+
+		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;
+		}
+
+	  function finish(type) {
+	    var p = pending[type],
+	        callback,
+	        urls;
+
+	    if (p) {
+	      callback = p.callback;
+	      urls     = p.urls;
+	      urls.shift();
+	      pollCount = 0;
+	      if (!urls.length) {
+	        callback && callback.call(p.context, p.obj);
+	        pending[type] = null;
+	        queue[type].length && load(type);
+	      }
+	    }
+	  }
+
+	  function getEnv() {
+	    var ua = navigator.userAgent;
+
+	    env = {
+
+	      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);
+	  }
+
+	  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) {
+
+	      urls = typeof urls === 'string' ? [urls] : urls.concat();
+
+	      if (isCSS || env.async || env.gecko || env.opera) {
+
+	        queue[type].push({
+	          urls    : urls,
+	          callback: callback,
+	          obj     : obj,
+	          context : context
+	        });
+	      } else {
+	        for (i = 0, len = urls.length; i < len; ++i) {
+	          queue[type].push({
+	            urls    : [urls[i]],
+	            callback: i === len - 1 ? callback : null,
+	            obj     : obj,
+	            context : context
+	          });
+	        }
+	      }
+	    }
+
+	    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)) {
+	        if (env.webkit) {
+	          p.urls[i] = node.href; 
+	          pollWebKit();
+	        } else {
+	          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]);
+	    }
+	  }
+
+	  function pollGecko(node) {
+	    var hasRules;
+
+	    try {
+
+	      hasRules = !!node.sheet.cssRules;
+	    } catch (ex) {
+	      pollCount += 1;
+
+	      if (pollCount < 200) {
+	        setTimeout(function () { pollGecko(node); }, 50);
+	      } else {
+
+	        hasRules && finish('css');
+	      }
+
+	      return;
+	    }
+
+	    finish('css');
+	  }
+
+	  function pollWebKit() {
+	    var css = pending.css, i;
+
+	    if (css) {
+	      i = styleSheets.length;
+
+	      while (--i >= 0) {
+	        if (styleSheets[i].href === css.urls[0]) {
+	          finish('css');
+	          break;
+	        }
+	      }
+
+	      pollCount += 1;
+
+	      if (css) {
+	        if (pollCount < 200) {
+	          setTimeout(pollWebKit, 50);
+	        } else {
+
+	          finish('css');
+	        }
+	      }
+	    }
+	  }
+
+	  return {
+
+		css: function (urls, callback, obj, context) {
+			if (isLoaded(urls)) {
+				return callback;
+			} else {
+				load('css', urls, callback, obj, context);
+			}
+		},
+
+		js: function (urls, callback, obj, context) {
+			if (isLoaded(urls)) {
+				return callback;
+			} else {
+				load('js', urls, callback, obj, context);
+			}
+		}
+
+	  };
+	})(this.document);
+}
+