function wfgundong(id,id1,id2,speed){
	//无缝滚动
	//speed数字越大速度越慢
	var obj = document.getelementbyid(id)
	var obj1 = document.getelementbyid(id1)
	var obj2 = document.getelementbyid(id2)
	obj2.innerhtml=obj1.innerhtml; //克隆demo1为demo2
	function marquee(){
	if(obj2.offsetheight-obj.scrolltop<=0)//当滚动至demo1与demo2交界时
	obj.scrolltop-=obj1.offsetheight //demo跳到最顶端
	else{
	obj.scrolltop++
	}
	}

	var mymar=setinterval(marquee,speed);
	obj.onmouseover=function() {clearinterval(mymar)};//鼠标移上时清除定时器达到滚动停止的目的
	obj.onmouseout=function() {mymar=setinterval(marquee,speed)};//鼠标移开时重设定时器
}