firefox 2 marquee兼容

新作的项目里面有个页面用到了<marquee>标签结果，在firefox下面就是不工作。无奈写了一段代码，用来替代简单的marquee功能：

 

/*
 * parameter: el -- marquee element
 * 
 * html structure:
 * <div ...>
 * 	<marquee ...>
 * 		<table width="770px"...>
 */
Marquee = function(el){
	el.parentNode.style.overflow = "hidden";
	el.parentNode.style.position = "relative";
	
	var tab = el.getElementsByTagName("table")[0];
	el.parentNode.appendChild(tab);
	el.parentNode.removeChild(el);
	el = tab;
	el.style.position = "absolute";
	el.style.left = "0px";
	
	pfun = this;
	
	this.pauseflag = false;
	el.onmouseover = function(){pfun.pause()};
	el.onmouseout = function(){pfun.resume()};
	
	this.direction = -1;
	
	this.timer = window.setInterval(function(){
		if(!pfun.pauseflag){
			var left = parseInt(el.style.left);
			
			/*
			 * table 里总共有10张图片一字排开，
			 * 长度770px,这里使用540px，
			 * 原因是考虑到最后3幅图片不能全部飞过，
			 * 否则会有一段间隙显示空白
			 */
			if(left < 0 && left <= -540){
				pfun.direction = 1
			}else if(left >= 0){
				pfun.direction = -1;
			}
			el.style.left = (left + (5*pfun.direction))+"px";
		}
	}, 200);
}

Marquee.prototype = {
	pause : function(){
		this.pauseflag = true;
	},
	
	resume : function(){
		this.pauseflag = false;
	}
}

/*
 * check is firefox 2.x
 */
if (/Firefox[\/\s](\d+\.\d+)/.test(navigator.userAgent)){
	var ffversion=new Number(RegExp.$1) // capture x.x portion and store as a number
	 if (ffversion>=2 && ffversion <= 3){
		 var els = document.getElementsByTagName("marquee");
		 for(var i = 0 ; i < els.length; i++)
			 new Marquee(els[i]);
	 }
}

 HTML代码：

...
</marquee>
<script type="text/javascript" src="js/marquee.js"></script>