网页特效，仿雅虎右侧的菜单代码特效

<style type="text/css">  </style> <SCRIPT LANGUAGE="JavaScript1.2"> adTime=5; //关闭窗口等待的时间 chanceAd=1; var ns=(document.layers); var ie=(document.all); var w3=(document.getElementById && !ie); adCount=0; function initAd(){ if(!ns && !ie && !w3) return; if(ie) adDiv=eval('document.all.sponsorAdDiv.style'); else if(ns) adDiv=eval('document.layers["sponsorAdDiv"]'); else if(w3) adDiv=eval('document.getElementById("sponsorAdDiv").style'); randAd=Math.ceil(Math.random()*chanceAd); if (ie||w3) adDiv.visibility="visible"; else adDiv.visibility ="show"; if(randAd==1) showAd(); } function showAd(){ if(adCount<adTime*10){adCount+=1; if (ie){documentWidth =document.body.offsetWidth/2+document.body.scrollLeft-20; documentHeight =document.body.offsetHeight/2+document.body.scrollTop-20;} else if (ns){documentWidth=window.innerWidth/2+window.pageXOffset-20; documentHeight=window.innerHeight/2+window.pageYOffset-20;} else if (w3){documentWidth=self.innerWidth/2+window.pageXOffset-20; documentHeight=self.innerHeight/2+window.pageYOffset-20;} adDiv.left=documentWidth-200;adDiv.top =documentHeight-200; setTimeout("showAd()",100);}else closeAd(); } function closeAd(){ if (ie||w3) adDiv.display="none"; else adDiv.visibility ="hide"; } onload=initAd; </script> <div id="sponsorAdDiv" style="visibility:hidden"> <table width="450" height="350" bgcolor="008000"><tr><td> <table width="445" height="345" bgcolor="F0FFF0"><tr><td> <center>welcome to HTTP://WWW.WEBJX.COM!<BR><BR>这个窗口将在5秒后自动关闭</center> </td></tr></table></td></tr></table></div>