这个效果有问题 帮我看下逻辑上哪错了


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>向上下左右不间断无缝滚动图片的效果(兼容火狐和IE)- www.codefans.net</title>
</head>
<body>
<div id="colee" style="overflow:auto;height:250px;width:410px;">
    <div id="colee1">
        <img src="http://www.codefans.net/jscss/demoimg/200907/bg3.jpg">
        <img src="http://www.codefans.net/jscss/demoimg/200907/bg3.jpg">
        <img src="http://www.codefans.net/jscss/demoimg/200907/bg3.jpg">
        <img src="http://www.codefans.net/jscss/demoimg/200907/bg3.jpg">
        <img src="http://www.codefans.net/jscss/demoimg/200907/bg3.jpg">
    </div>
<div id="colee2"></div>
</div>
<script>
var speed=2;
var colee2=document.getElementById("colee2");
var colee1=document.getElementById("colee1");
var colee=document.getElementById("colee");
colee2.innerHTML=colee1.innerHTML; //克隆colee1为colee2
function Marquee1(){
//当滚动至colee1与colee2交界时
if(colee2.offsetTop-colee.scrollTop<=0){
colee.scrollTop-=colee1.offsetHeight; //colee跳到最顶端
}else{
colee.scrollTop++
}
}
var MyMar1=setInterval(Marquee1,speed)//设置定时器
//鼠标移上时清除定时器达到滚动停止的目的
colee.onmouseover=function() {clearInterval(MyMar1)}
//鼠标移开时重设定时器
colee.onmouseout=function(){MyMar1=setInterval(Marquee1,speed)}
</script>
<!--向上滚动代码结束-->
</body>
</html>