javascript实现文字无缝滚动效果

<dl id="marquee" class="marquee">
 <dt>
 <ul class="right-content">
 <li>
 <a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="orderNum">BKCSHC161014002153</a> 
 </li>
 <li>
 <a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="orderNum">BKCSHC161014002153</a> 
 </li>
 <li>
 <a href="#" rel="external nofollow" rel="external nofollow" rel="external nofollow" class="orderNum">BKCSHC161014002153</a> 
 </li>
 ...
 </ul>
 </dt>
 <dd></dd>
</dl>

<script>
 $(function(){
 Marquee("marquee");
 })

 //订单滚动
 var Marquee = function(id){
 var container = document.getElementById(id), 
 original = container.getElementsByTagName("dt")[0], 
 clone = container.getElementsByTagName("dd")[0],
 liLength=original.getElementsByTagName("li").length,
 speed = 55;
 if(liLength<=8){
 return
 }
 clone.innerHTML = original.innerHTML;

 var rolling = function(){
 if (container.scrollTop === clone.offsetHeight) {
 container.scrollTop = 0;
 }
 else {
 container.scrollTop++;
 }
 }
 var timer = setInterval(rolling, speed)//设置定时器
 container.onmouseover = function(){
 clearInterval(timer)
 }//鼠标移到marquee上时，清除定时器，停止滚动
 container.onmouseout = function(){
 timer = setInterval(rolling, speed)
 }//鼠标移开时重设定时器
 } 
 </script>