var scrrol_top=0;
// javascript document
function $d(element){
	if(arguments.length>1){
		for(var i=0,length=arguments.length,elements=[];i<length;i++){
			elements.push($d(arguments[i]));
		}
		return elements;
	}
	if(typeof element=="string"){
		return document.getelementbyid(element);
	}else{
		return element;
	}
}
//类创建函数
var class={
	create:function(){
		return function(){
			this.initialize.apply(this,arguments);
		}
	}
}
//对象属性方法扩展
function.prototype.bind=function(object){
	var method=this;
	return function(){
		method.apply(object,arguments);
	}
}
var floatad=class.create();
floatad.prototype={
	initialize:function(id,top){
		this.id=$d(id);
		this.id.style.position="absolute";
		this.top=top||80;
		this.id.style.right="0px";
		this.id.style.top=this.top+"px";
		this.interid=setinterval(this.scroll.bind(this),30);
	},
	scroll:function(){
		this.stmnstartpoint = parseint(this.id.style.top,10);
		this.stmnendpoint =document.documentelement.scrolltop+ this.top;
		if(navigator.useragent.indexof("chrome")>0){
			this.stmnendpoint=document.body.scrolltop+this.top;	
		}

if (this.stmnstartpoint != this.stmnendpoint) {

    this.stmnscrollamount = math.ceil(math.abs(this.stmnendpoint - this.stmnstartpoint) / 15);

    this.id.style.top = parseint(this.id.style.top, 10) + ((this.stmnendpoint < this.stmnstartpoint) ? -this.stmnscrollamount : this.stmnscrollamount) + "px";

}
	}
}

function hide(){ 
float.style.visibility='hidden'; 
}