var d=1,obj=document.getElementById("Layer1");
function move()
{
    var ch=document.documentElement.clientHeight;
    var p=parseInt(document.documentElement.scrollTop);
    var top=parseInt(obj.style.top);
	if(top<p){d=1;top=p;}else if(top>p+ch-38){d=0;top=p+ch-38;}
	if(d){obj.style.top =top+1+'px';}else{obj.style.top =top-1+'px';}
	MyMar = setTimeout("move()",30);
}
move();

obj.onmouseover=function(){clearTimeout(MyMar);}
obj.onmouseout=function(){move();}