<!--
    var speed=30; //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)};
    -->