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>