function next(elem){    
        do{    
            elem=elem.nextSibling;    
        }while(elem&&elem.nodeType!=1);    
        return elem;    
    }    
    //---查找第一个子元素的函数---//    
    function first(elem){    
        elem=elem.firstChild;    
        return elem && elem.nodeType!=1?next(elem):elem;    
    }
	
	var Marquee = {
		init : function(id,toFollow,speed){
			this.speed = speed || 10;
			this.boxID = id;
			this.toFollow=toFollow;
			this.scrollBox = document.getElementById(id);
			
			if(this.toFollow=="top"||this.toFollow=="bottom"){
				this.appendBox=first(this.scrollBox).cloneNode(true);
				this.scrollBox.appendChild(this.appendBox);
			}else{
				var templateLeft = "<table cellspacing='0' cellpadding='0' style='border-collapse:collapse;display:inline;'><tr><td noWrap=true style='white-space: nowrap;word-break:keep-all;'>"+this.scrollBox.innerHTML+"</td><td noWrap=true style='white-space: nowrap;word-break:keep-all;'>"+this.scrollBox.innerHTML+"</td></tr></table>";
				this.scrollBox.innerHTML=templateLeft;
				this.appendBox=first(first(first(first(this.scrollBox))));
			}
			this.objs = {
				scrollBox : this.scrollBox,
				appendBox : this.appendBox,
				toFollow : this.toFollow,
				speed : this.speed,
				id : this.boxID
			};
			return this;
		},

		scrollUp : function(){
			var self = this.objs;
			self.begin = function(){
				if(self['toFollow']=="top"){
					self.doScr = setInterval(function(){
						if(self['appendBox'].offsetHeight<=self['scrollBox'].scrollTop){
							self['scrollBox'].scrollTop-=first(self['scrollBox']).offsetHeight;
						}else{
							self['scrollBox'].scrollTop++;
						}
					},self.speed);
				}else if(self['toFollow']=="bottom"){
				self.doScr = setInterval(function(){
					if(self['scrollBox'].scrollTop<=0){
						self['scrollBox'].scrollTop=self['appendBox'].offsetHeight;
					}else{
						self['scrollBox'].scrollTop--;
					}
				},self.speed);
			}else if(self['toFollow']=="left"){
				self.doScr = setInterval(function(){
					if(self['appendBox'].offsetWidth<=self['scrollBox'].scrollLeft){
						self['scrollBox'].scrollLeft-=self['appendBox'].offsetWidth;
					}else{
						self['scrollBox'].scrollLeft++;
					}
				},self.speed);
			}else if(self['toFollow']=="right"){
				self.doScr = setInterval(function(){
					if(self['scrollBox'].scrollLeft<=0){
						self['scrollBox'].scrollLeft=self['appendBox'].offsetWidth;
					}else{
						self['scrollBox'].scrollLeft--;
					}
					
				},self.speed);
				
			}
			}
			self.begin();
			self.scrollBox.onmouseover = function(){
				clearInterval(self.doScr);
			}
			self.scrollBox.onmouseout = function(){
				self.begin();
			}
		}
	}

//	Marquee.init("demo","top").scrollUp();
//	Marquee.init("demo2","bottom", 50).scrollUp();
//	Marquee.init("demo3","left").scrollUp();
//	Marquee.init("demo4","right", 50).scrollUp();