I have some JS that animates a sliding navbar on my site.

When viewing http://twisted-reality.co.uk using IE8 iexplorer.exe hogs around 80% of my CPU when in focus and around 20% when not in focus.

I don't have this problem with IE7, Firefox, Opera etc...

Here is the code that I think is causing the problem :

Code:
<!-- START FLOAT 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;
      this.sP(this.cx, this.cy);
      setTimeout(this.id + "_obj.floatIt()", 40);
    }
    return el;
  }
  JSFX_FloatDiv("navbar", 106,118).floatIt();
  -->
  </script>
  <!-- ********************************************************* -->
  <!-- END FLOAT SCRIPT -->
I don't particularly want to use conditional statements to give IE8 a different navbar.

Hope someone can help