js实现文字列表无缝滚动效果

<div id="rule">        <div class="list" id="list">          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>          <p>用户185****0000  获得XXX优惠券</p>        </div>   <div class="list2" id="list2"></div></div>

var speed=50;var list=document.getElementById('list');var list2=document.getElementById('list2');var rule=document.getElementById('rule');list2.innerHTML=list.innerHTML;function Marquee(){  if(list2.offsetTop-rule.scrollTop<=0)    rule.scrollTop-=list.offsetHeight;  else{    rule.scrollTop++;  }}var MyMar=setInterval(Marquee,speed);rule.onmouseover=function() {clearInterval(MyMar)}rule.onmouseout=function() {MyMar=setInterval(Marquee,speed)}