var speed=15; //数字越大速度越慢
var taba=document.getElementById("demoa");
var tab1a=document.getElementById("demo1a");
var tab2a=document.getElementById("demo2a");
tab2a.innerHTML=tab1a.innerHTML;
function Marquee(){
if(tab2a.offsetWidth-taba.scrollLeft<=0)
taba.scrollLeft-=tab1a.offsetWidth
else{
taba.scrollLeft++;
}
}
var MyMar=setInterval(Marquee,speed);
taba.onmouseover=function() {clearInterval(MyMar)};
taba.onmouseout=function() {MyMar=setInterval(Marquee,speed)};