javascript 无间断滚动代码

<div id=demo style=overflow:hidden;height:145;width:200;background:#FFFFFF;color:#000000>
<div id=demo1>
<!-- 定义图片 -->
<img src="img/list1.jpg" width="200" height="145" />
<img src="img/list2.jpg" width="200" height="145" />
<img src="img/list3.jpg" width="200" height="145" />
<img src="img/list4.jpg" width="200" height="145" />
<img src="img/list5.jpg" width="200" height="145" />
</div>
<div id=demo2></div>
</div>

<script>
var speed=30
demo2.innerHTML=demo1.innerHTML
function Marquee(){
if(demo2.offsetTop-demo.scrollTop<=0)
demo.scrollTop-=demo1.offsetHeight
else{
demo.scrollTop++
}
}
var MyMar=setInterval(Marquee,speed)
demo.onmouseover=function() {clearInterval(MyMar)}
demo.onmouseout=function() {MyMar=setInterval(Marquee,speed)}
</script>
</div>