Ext JS是一个创建丰富互联网应用程序的跨浏览器的JavaScrip库。它包含：高效率

				/*
				 * Ext JS Library 3.0 Pre-alpha
				 * Copyright(c) 2006-2008, Ext JS, LLC.
				 * licensing@extjs.com
				 * 
				 * http://extjs.com/license
				 */
				
					
					if(Ext.isIE) {
				        function fnCleanUp() {
				            var p = Function.prototype;
				            delete p.createSequence;
				            delete p.defer;
				            delete p.createDelegate;
				            delete p.createCallback;
				            delete p.createInterceptor;
				
				            window.detachEvent("onunload", fnCleanUp);
				        }
				        window.attachEvent("onunload", fnCleanUp);
				    }
				})();