@@@ 连续滚动新问题

@@@ 连续滚动代码嵌入表格后，浏览的时候网页下方为什么会出现空白
代码如下
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<!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>无标题文档</title>
<style type="text/css">
<!--
body {
background-color: #CCCCCC;
margin-left: 0px;
margin-top: 0px;
margin-right: 0px;
margin-bottom: 0px;
}
-->
</style></head>

<body>

<table width="638" height="500" border="0" cellpadding="0" cellspacing="0" bgcolor="#FFCC33">
<tr>
<td><div id="marquees">


<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
<a href="#" target="_blank">sdafdsahfkjdshfsd</a><br>
</div>
<script language="JavaScript">

marqueesHeight=400;
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()",10);
}
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>
</td>
<td> </td>
</tr>
</table>

</body>
</html>