无缝javascript滚动新闻

<div id="marquees">
<a href="javascript:">1,你可曾有过无数的梦想，</a><br>
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<a href="javascript:">2,却在时光的流逝里幻灭 </a><br>
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<a href="javascript:">3,你可曾对未来期待憧憬，</a><br>
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<a href="javascript:">4,却在成长的岁月中迷失</a><br>
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</div>
<script language="JavaScript">

marqueesHeight=200;
stopscroll=false;

with(marquees){
style.width=0;
style.height=marqueesHeight;
style.overflowX="visible";
style.overflowY="hidden";
noWrap=true;
onmouseover=new Function("stopscroll=true");
onmouseout=new Function("stopscroll=false");
}
document.write('<div id="templayer" style="position:absolute;z-index:1;visibility:hidden"></div>');

preTop=0; currentTop=0;

function init(){
templayer.innerHTML="";
while(templayer.offsetHeight<marqueesHeight){
templayer.innerHTML+=marquees.innerHTML;
}
marquees.innerHTML=templayer.innerHTML+templayer.innerHTML;
setInterval("scrollUp()",20);//越大越慢
}
document.body.onload=init;

function scrollUp(){
if(stopscroll==true) return;
preTop=marquees.scrollTop;
marquees.scrollTop+=1;
if(preTop==marquees.scrollTop){
marquees.scrollTop=templayer.offsetHeight-marqueesHeight;
marquees.scrollTop+=1;
}
}
</script>