var speed3=25//速度数值越大速度越慢
demo2.innerHTML=demo1.innerHTML
function Marquee()
{
    if(demo2.offsetWidth-demo.scrollLeft<=0)
        demo.scrollLeft-=demo1.offsetWidth
    else
    {
        demo.scrollLeft++
    }
}
var MyMar=setInterval(Marquee,speed3)
demo.onmouseover=function() {clearInterval(MyMar)}
demo.onmouseout=function() {MyMar=setInterval(Marquee,speed3)}