向上无缝滚动

<DIV id=demo style="OVERFLOW: hidden; HEIGHT: 150px">
<DIV id=demo1>
<table width="237" border="0" cellspacing="0" cellpadding="0">
<tr>
<td height="25">·<a href="#">公告标题</a></td>
</tr>
<tr>
<td height="25">·<a href="#">公告标题</a></td>
</tr>
<tr>
<td height="25">·<a href="#">公告标题</a></td>
</tr>
<tr>
<td height="25">·<a href="#">公告标题</a></td>
</tr>
<tr>
<td height="25">·<a href="#">公告标题</a></td>
</tr>
<tr>
<td height="25">·<a href="#">公告标题</a></td>
</tr>
</table>
</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. {clearInterval(MyMar)}
demo. {MyMar=setInterval(Marquee,speed)}
</SCRIPT>