lastScrollY=0;


var bodyH=(parseInt(document.body.clientHeight)-500-leftH)/2;

function heartBeat(){
var diffY;
var topNo;

if (document.documentElement && document.documentElement.scrollTop)
diffY = document.documentElement.scrollTop;
else if (document.body)
diffY = document.body.scrollTop
else
{/*Netscape stuff*/}
//alert(diffY);
percent=.1*(diffY-lastScrollY);
if(percent>0)percent=Math.ceil(percent);
else percent=Math.floor(percent);
var topNo=parseInt(document.getElementById("LeftAd").style.top)+percent;



if(topNo>10&&topNo<bodyH)
{
document.getElementById("LeftAd").style.top=topNo+"px";
}

lastScrollY=lastScrollY+percent;



}


window.setInterval("heartBeat()",1);