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*/}

//alert(diffY);

percent=.1*(diffY-lastScrollY); 
if(percent>0)percent=Math.ceil(percent); 
else percent=Math.floor(percent); 
document.getElementById("floIM").style.top=parseInt(document.getElementById
("floIM").style.top)+percent+"px";

lastScrollY=lastScrollY+percent; 
//alert(lastScrollY);
}
window.setInterval("heartBeat()",1);