JS连续向上滚动代码

<SCRIPT language=JavaScript>
<!--
try{
  var marqueesHeight = 58;
  var stopscroll     = false;

  var scrollElem = document.getElementById("icefable1");
  with(scrollElem){
    style.width     = 480;
    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("box16left");

  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 == 22) {
    stoptime += 1;
    currentTop -= 1;
    if(stoptime == 100) {
      currentTop = 0;
      stoptime = 0;
    }
  }else{
    preTop = scrollElem.scrollTop;
    scrollElem.scrollTop += 2;
    if(preTop == scrollElem.scrollTop){
      scrollElem.scrollTop = 0;
      scrollElem.scrollTop += 2;
    }
  }
}
//-->
</SCRIPT>