//滚动速度设置，数越大越慢 
var speed=60; 
//demo2复制demo1的内容 
demo2.innerHTML=demo1.innerHTML; 
//滚动函数 
function Marquee() 
{ 
 if(demo2.offsetTop-demo.scrollTop<=0) 
  demo.scrollTop-=demo1.offsetHeight; 
 else 
  demo.scrollTop++; 
} 
//滚动 
var MyMar=setInterval(Marquee,speed); 
//鼠标放上停止滚动 
demo.onmouseover=function(){clearInterval(MyMar);} 
//鼠标离开继续滚动 
demo.onmouseout=function(){MyMar=setInterval(Marquee,speed);}