// JavaScript Document

       var speed=10; //数字越大速度越慢
       var tab=document.getElementById("demo");
       var tab1=document.getElementById("demo1");
       var tab2=document.getElementById("demo2");
       tab2.innerHTML=tab1.innerHTML;
       function Marquee(){
       if(tab2.offsetWidth-tab.scrollLeft<=0)
       tab.scrollLeft-=tab1.offsetWidth
       else{
       tab.scrollLeft++;
       }
       }
       var MyMar=setInterval(Marquee,speed);
       tab.onmouseover=function() {clearInterval(MyMar)};
       tab.onmouseout=function() {MyMar=setInterval(Marquee,speed)};