javascript对联广告代码

<script language="JavaScript" type="text/javascript">
lastScrollY=0;
function heartBeat(){
var diffY;
if (document.documentElement && document.documentElement.scrollTop)
diffY = document.documentElement.scrollTop;
else if (document.body)
diffY = document.body.scrollTop
else
{/*Netscape stuff*/}
percent=.1*(diffY-lastScrollY);
if(percent>0)percent=Math.ceil(percent);
else percent=Math.floor(percent);
document.getElementById("lovexin12").style.top=parseInt(document.getElementById
("lovexin12").style.top)+percent+"px";
document.getElementById("lovexin14").style.top=parseInt(document.getElementById
("lovexin12").style.top)+percent+"px";
lastScrollY=lastScrollY+percent;
}
suspendcode12="<DIV id=\"lovexin12\" style='left:2px;POSITION:absolute;TOP:120px;'>ad1</div>"
suspendcode14="<DIV id=\"lovexin14\" style='right:2px;POSITION:absolute;TOP:120px;'>ad2</div>"
document.write(suspendcode12);
document.write(suspendcode14);
window.setInterval("heartBeat()",1);
</script>