var speed=10; //数字越大速度越慢
            var tab=document.getelementbyid("scroll");
            var tab1=document.getelementbyid("scroll_begin");
            var tab2=document.getelementbyid("scroll_end");
            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)};