var speed=40;  //设置文字滚动速度
   dome2.innerHTML=dome1.innerHTML //复制dome1为dome2
   function Marquee(){
   //alert(dome1.offsetHeight);
   //alert(dome2.offsetTop-dome.scrollTop);
   if(dome2.offsetTop-dome.scrollTop<=0) //当滚动至dome1与dome2交界时
    dome.scrollTop-=dome1.offsetHeight  //dome跳到最顶端
   else{
    dome.scrollTop++;
   }
   }
   var MyMar=setInterval(Marquee,speed) //设置定时器
   dome.onmouseover=function() {clearInterval(MyMar)}//鼠标移上时清除定时器达到滚动停止的目的
   dome.onmouseout=function() {MyMar=setInterval(Marquee,speed)}//鼠标移开时重设定时器，继续滚动