FirFox 也可用outerHTML

 if(window.HTMLElement) {
    HTMLElement.prototype.__defineSetter__("outerHTML",function(sHTML){
        var r=this.ownerDocument.createRange();
        r.setStartBefore(this);
        var df=r.createContextualFragment(sHTML);
        this.parentNode.replaceChild(df,this);
        return sHTML;
        });

    HTMLElement.prototype.__defineGetter__("outerHTML",function(){
     var attr;
        var attrs=this.attributes;
        var str="<"+this.tagName.toLowerCase();
        for(var i=0;i<attrs.length;i++){
            attr=attrs[i];
            if(attr.specified)
                str+=" "+attr.name+'="'+attr.value+'"';
            }
        if(!this.canHaveChildren)
            return str+">";
        return str+">"+this.innerHTML+"</"+this.tagName.toLowerCase()+">";
        });
      
 HTMLElement.prototype.__defineGetter__("canHaveChildren",function(){
  switch(this.tagName.toLowerCase()){
            case "area":
            case "base":
         case "basefont":
            case "col":
            case "frame":
            case "hr":
            case "img":
            case "br":
            case "input":
            case "isindex":
            case "link":
            case "meta":
            case "param":
            return false;
        }
        return true;

     });
}