javascript广告浮动效果问题，请各位老大们务必帮小弟看看。在线等急用。

<script language="JavaScript">
<!--
if(parseInt(navigator.appVersion.charAt(0))<4){
location.href="http://www.monet.cn"
}var mvtLight="image/car.gif"
var mvtWidth=90
var mvtHeight=90
var mvtLink="http://www.monet.cn"
var mvtAlt="http://www.monet.cn"brOK=navigator.javaEnabled()?true:false
ns4=(document.layers)?true:false
ie4=(document.all)?true:falseif(ns4){
document.write('<layer id="mvt" width=40 height=60;"><a href="'+mvtLink+'" target=_blank id="imgLink"><img src="'+mvtLight+'" border=0 width="'+mvtWidth+'" height="'+mvtHeight+'" alt="'+mvtAlt+'" id="moveImg"><\/a><\/layer>');
}
else{
document.write('<div id="mvt" style="position:absolute; width:40; height:60;"><a href="'+mvtLink+'" target=_blank id="imgLink"><img src="'+mvtLight+'" border=0 width="'+mvtWidth+'" height="'+mvtHeight+'" alt="'+mvtAlt+'" id="moveImg"><\/a><\/div>');
}var vmin=2;
var vmax=5;
var vr=2;
var timer1;function Chip(chipname,width,height)
{
this.named=chipname;
this.vx=vmin+vmax*Math.random();
this.vy=vmin+vmax*Math.random();
this.w=width;
this.h=height;
this.xx=0;
this.yy=0;
this.timer1=null;
}function movechip(chipname)
{
if(brOK)
{eval("chip="+chipname);
if(ns4)
{pageX=window.pageXOffset;
pageW=window.innerWidth;
pageY=window.pageYOffset;
pageH=window.innerHeight;
}
else
{pageX=window.document.body.scrollLeft;
pageW=window.document.body.offsetWidth-8;
pageY=window.document.body.scrollTop;
pageH=window.document.body.offsetHeight;
}chip.xx=chip.xx+chip.vx;
chip.yy=chip.yy+chip.vy;chip.vx+=vr*(Math.random()-0.5);
chip.vy+=vr*(Math.random()-0.5);
if(chip.vx>(vmax+vmin)) chip.vx=(vmax+vmin)*2-chip.vx;
if(chip.vx<(-vmax-vmin)) chip.vx=(-vmax-vmin)*2-chip.vx;
if(chip.vy>(vmax+vmin)) chip.vy=(vmax+vmin)*2-chip.vy;
if(chip.vy<(-vmax-vmin)) chip.vy=(-vmax-vmin)*2-chip.vy;
if(chip.xx<=pageX)
{ chip.xx=pageX;
chip.vx=vmin+vmax*Math.random();
}
if(chip.xx>=pageX+pageW-chip.w)
{ chip.xx=pageX+pageW-chip.w;
chip.vx=-vmin-vmax*Math.random();
}
if(chip.yy<=pageY)
{ chip.yy=pageY;
chip.vy=vmin+vmax*Math.random();
}
if(chip.yy>=pageY+pageH-chip.h)
{ chip.yy=pageY+pageH-chip.h;
chip.vy=-vmin-vmax*Math.random();
}if(ns4){
eval('document.'+chip.named+'.top ='+chip.yy);
eval('document.'+chip.named+'.left='+chip.xx);
}
else{
eval('document.all.'+chip.named+'.style.pixelLeft='+chip.xx);
eval('document.all.'+chip.named+'.style.pixelTop ='+chip.yy);
}
chip.timer1=setTimeout("movechip('"+chip.named+"')",100); //设置速度，数值越大速度越慢
}
}function stopme(chipname)
{if(brOK)
{//alert(chipname)
eval("chip="+chipname);
if(chip.timer1!=null)
{clearTimeout(chip.timer1)}
}
}var mvt;
function mvt()
{
mvt=new Chip("mvt",60,80);
if(brOK){
movechip("mvt");
}
setInterval( "changeImg()", 3000 );
}window.onload=mvtvar img = [
["http://www.163.com/images/neteaselogo.gif", "http://www.163.com"],
["http://images.sohu.com/uiue/sohu_logo/2005/index_logo.gif", "http://www.sohu.com"],
["http://www.baidu.com/img/logo-yy.gif", "http://www.baidu.com"],
["http://www.google.com/images/logo_sm.gif", "http://www.google.com"]
  ];
var p = 0;function changeImg()
{
if( p >= img.length )
p = 0;
var imgLink = document.getElementById("imgLink");
var moveImg = document.getElementById("moveImg");
moveImg.src = img[p][0];
imgLink.href= img[p][1];
p++;
}
//-->
</script>