var speed =100;//速度数值越大速度越慢
    document.getElementById("a2").innerHTML = document.getElementById("a1").innerHTML;
    function Marquee4() {
        if (document.getElementById("gundong").scrollLeft >=878)
            document.getElementById("gundong").scrollLeft =0;
        else {
            document.getElementById("gundong").scrollLeft++;
        }
    }
    var MyMar4 = setInterval(Marquee4, speed);
    document.getElementById("gundong").onmouseover = function() { clearInterval(MyMar4); }
    document.getElementById("gundong").onmouseout = function() { MyMar4 = setInterval(Marquee4, speed); }