JavaScript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)}