Floating Script Problems

I have problems flatting script menu, I use this script,

<script type="text/javascript">
var ns = (navigator.appName.indexOf("Netscape") != -1);
var d = document;
function JSFX_FloatDiv(id, sx, sy)
{
var el=d.getElementById?d.getElementById(id):d.all?d.all[id]:d.layers[id];
var px = document.layers ? "" : "px";
window[id + "_obj"] = el;
if(d.layers)el.style=el;
el.cx = el.sx = sx;el.cy = el.sy = sy;
el.sP=function(x,y){this.style.left=x+px;this.style.top=y+px;};

el.floatIt=function()
{
var pX, pY;
pX = (this.sx >= 0) ? 0 : ns ? innerWidth :
document.documentElement && document.documentElement.clientWidth ?
document.documentElement.clientWidth : document.body.clientWidth;
pY = ns ? pageYOffset : document.documentElement && document.documentElement.scrollTop ?
document.documentElement.scrollTop : document.body.scrollTop;
if(this.sy<0)
pY += ns ? innerHeight : document.documentElement && document.documentElement.clientHeight ?
document.documentElement.clientHeight : document.body.clientHeight;
this.cx += (pX + this.sx - this.cx)/8;this.cy += (pY + this.sy - this.cy)/8;
if(this.cy<=1815)
{
this.sP(this.cx, this.cy+60);
}
else if(this.cy>1500)
{

this.sP(this.cx, this.cy-35);
}
//alert(this.cy);
setTimeout(this.id + "_obj.floatIt()", 40);
}
return el;
}
JSFX_FloatDiv("divTopLeft", 5,78).floatIt();
</script>
<!-- ********************************************************* -->
problems is this when page scroll menu up the header and footer, I want to menu away footer and header plez help.