// JavaScript Document
var speed=20; //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)};