在Dom树加载后执行，jQuery中的ready
(function(){ var isReady=false;//判断onDOMReady方法是否已经被执行过 var readyList= [];//把需要执行的方法先暂存在这个数组里 var timer;//定时器句柄 ready=function(fn) { if (isReady ) fn.call( document); else readyList.push( function() { return fn.call(this);}); return this; } var onDOMReady=function(){ for(var i=0;i<readyList.length;i++){ readyList[i].apply(document); } readyList = null; } var bindReady = function(evt){ if(isReady) return; isReady=true; onDOMReady.call(window); if(document.removeEventListener){ document.removeEventListener("DOMContentLoaded", bindReady, false); }else if(document.attachEvent){ document.detachEvent("onreadystatechange", bindReady); if(window == window.top){ clearInterval(timer); timer = null; } } }; if(document.addEventListener){ document.addEventListener("DOMContentLoaded", bindReady, false); }else if(document.attachEvent){ document.attachEvent("onreadystatechange", function(){ if((/loaded|complete/).test(document.readyState)) bindReady(); }); if(window == window.top){ timer = setInterval(function(){ try{ //在IE下用能否执行doScroll判断dom是否加载完毕 isReady||document.documentElement.doScroll('left'); }catch(e){ return; } bindReady(); },5); } }})();