javascript实现无缝上下滚动特效

<div id="colee" style="overflow:hidden;height:100px;width:410px;border:1px solid red;">
<div id="colee1">
<p>php</p>
<p>java</p>
<p>ruby</p>
<p>python</p>
<p>www.phpddt.com</p>
</div>
<div id="colee2"></div>
</div>
<script>
//速度设置
var speed=1;
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>