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)};