var speedy=25//速度数值越大速度越慢
ym2.innerHTML=ym1.innerHTML
function Marqueey(){
if(ym2.offsetHeight-ym.scrollTop<=0)
ym.scrollTop-=ym1.offsetHeight
else{
ym.scrollTop++
}
}
var ymMar=setInterval(Marqueey,speedy)
ym.onmouseover=function() {clearInterval(ymMar)}
ym.onmouseout=function() {ymMar=setInterval(Marqueey,speedy)}