var speed=24;
demo2.innerHTML=demo1.innerHTML;	//克隆demo1为demo2

function Marquee(){
	if(demo2.offsetWidth  <= demo.scrollLeft){	//当滚动至demo1与demo2交界时
		demo.scrollLeft = demo.scrollLeft - demo1.offsetWidth;		//demo跳到最顶端
	}
	else{
		demo.scrollLeft++;
	}
}

var MyMar=setInterval(Marquee,speed);	//设置定时器

demo.onmouseover=function() {clearInterval(MyMar);}//鼠标移上时清除定时器达到滚动停止的目的
demo.onmouseout=function() {MyMar=setInterval(Marquee,speed);}//鼠标移开时重设定时器
// JavaScript Document:jiaoti