javascript 文字滚动代码 (ie和火狐通用)

<div id="andyscroll">
<div id="scrollmessage">
  <ul>
    <li><a href=../../html/2009-3/2009310003718_1.html title="2009年新现代学校联谊会"target=_blank>·2009年新现代学校联谊会</a></li><li><a href=../../html/2009-3/200936003705_1.html title="2009年北京自考本科毕业生申请学士学位"target=_blank>·2009年北京自考本科毕业生申请学士学位</a></li><li><a href=../../html/2009-2/200924003514_1.html title="2009年新现代学校春季开学通知"target=_blank>·2009年新现代学校春季开学通知</a></li><li><a href=../../html/2009-1/2009118003482_1.html title="北京2009年1月自考成绩查询时间通知"target=_blank>·北京2009年1月自考成绩查询时间通知</a></li>
  </ul>
</div>
</div>
 
<script type="text/javascript">
<!--
try{
  var marqueesHeight = 25;
  var stopscroll     = false;
 
  var scrollElem = document.getElementById("andyscroll");
  with(scrollElem){
    style.width     = 620;
    style.height    = marqueesHeight;
    style.overflow  = 'hidden';
    noWrap          = true;
  }
 
  scrollElem.onmouseover = new Function('stopscroll = true');
  scrollElem.onmouseout  = new Function('stopscroll = false');
 
  var preTop     = 0;
  var currentTop = 0;
  var stoptime   = 0;
 
      var leftElem = document.getElementById("scrollmessage");
  scrollElem.appendChild(leftElem.cloneNode(true));
  init_srolltext();
 
}catch(e){}
 
function init_srolltext(){
  scrollElem.scrollTop = 0;
  setInterval('scrollUp()', 15);
}
 
function scrollUp(){
  if(stopscroll) return;
  currentTop += 1;
  if(currentTop == 26){
    stoptime += 1;
    currentTop -= 1;
    if(stoptime == 150){
      currentTop = 0;
      stoptime = 0;
    }
  }else{
    preTop = scrollElem.scrollTop;
    scrollElem.scrollTop += 1;
    if(preTop == scrollElem.scrollTop){
      scrollElem.scrollTop = 0;
      scrollElem.scrollTop += 1;
    }
  }
}
//-->
</script>
</div>
</div>