JS hogging CPU ?

[Twisted_Daemon]

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 :

<!-- 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

[chestertondevelopment]

I haven't got time to look at the script, sorry, but I wouldn't be too bothered about IE8 being slow at the moment, it's only a beta and it's probably going to change a lot by the time it's released.

[Twisted_Daemon]

I'm just concerned that if this is the way that IE8 will be handling JS my site will suck the users resources dry.

I'm not entirely sure if the problem lies within the script or IE8...