var speed=10; //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)};