IE有很多好用的扩展是firefox 不支持的，比如firefox不支持children属性，还有很多，网上见到一些扩张的代码，摘录如下

<script language="JavaScript" type="Text/JavaScript">
<!--
if(window.Event){// 修正Event的DOM
    /*
                                IE5        MacIE5        Mozilla        Konqueror2.2        Opera5
    event                        yes        yes            yes            yes                    yes
    event.returnValue            yes        yes            no            no                    no
    event.cancelBubble            yes        yes            no            no                    no
    event.srcElement            yes        yes            no            no                    no
    event.fromElement            yes        yes            no            no                    no
    
    */
    Event.prototype.__defineSetter__("returnValue",function(b){// 
        if(!b)this.preventDefault();
        return b;
        });
    Event.prototype.__defineSetter__("cancelBubble",function(b){// 设置或者检索当前事件句柄的层次冒泡
        if(b)this.stopPropagation();
        return b;
        });
    Event.prototype.__defineGetter__("srcElement",function(){
        var node=this.target;
        while(node.nodeType!=1)node=node.parentNode;
        return node;
        });
    Event.prototype.__defineGetter__("fromElement",function(){// 返回鼠标移出的源节点
        var node;
        if(this.type=="mouseover")
            node=this.relatedTarget;
        else if(this.type=="mouseout")
            node=this.target;
        if(!node)return;
        while(node.nodeType!=1)node=node.parentNode;
        return node;
        });
    Event.prototype.__defineGetter__("toElement",function(){// 返回鼠标移入的源节点
        var node;
        if(this.type=="mouseout")
            node=this.relatedTarget;
        else if(this.type=="mouseover")
            node=this.target;
        if(!node)return;
        while(node.nodeType!=1)node=node.parentNode;
        return node;
        });
    Event.prototype.__defineGetter__("offsetX",function(){
        return this.layerX;
        });
    Event.prototype.__defineGetter__("offsetY",function(){
        return this.layerY;
        });
    }
if(window.Document){// 修正Document的DOM
    /*
                                IE5        MacIE5        Mozilla        Konqueror2.2        Opera5
    document.documentElement    yes        yes            yes            yes                    no
    document.activeElement        yes        null        no            no                    no
    
    */
    }
if(window.Node){// 修正Node的DOM
    /*
                                IE5        MacIE5        Mozilla        Konqueror2.2        Opera5
    Node.contains                yes        yes            no            no                    yes
    Node.replaceNode            yes        no            no            no                    no
    Node.removeNode                yes        no            no            no                    no
    Node.children                yes        yes            no            no                    no
    Node.hasChildNodes            yes        yes            yes            yes                    no
    Node.childNodes                yes        yes            yes            yes                    no
    Node.swapNode                yes        no            no            no                    no
    Node.currentStyle            yes        yes            no            no                    no
    
    */
    Node.prototype.replaceNode=function(Node){// 替换指定节点
        this.parentNode.replaceChild(Node,this);
        }
    Node.prototype.removeNode=function(removeChildren){// 删除指定节点
        if(removeChildren)
            return this.parentNode.removeChild(this);
        else{
            var range=document.createRange();
            range.selectNodeContents(this);
            return this.parentNode.replaceChild(range.extractContents(),this);
            }
        }
    Node.prototype.swapNode=function(Node){// 交换节点
        var nextSibling=this.nextSibling;
        var parentNode=this.parentNode;
        node.parentNode.replaceChild(this,Node);
        parentNode.insertBefore(node,nextSibling);
        }
    }
if(window.HTMLElement){
    HTMLElement.prototype.__defineGetter__("all",function(){
        var a=this.getElementsByTagName("*");
        var node=this;
        a.tags=function(sTagName){
            return node.getElementsByTagName(sTagName);
            }
        return a;
        });
    HTMLElement.prototype.__defineGetter__("parentElement",function(){
        if(this.parentNode==this.ownerDocument)return null;
        return this.parentNode;
        });
    HTMLElement.prototype.__defineGetter__("children",function(){
        var tmp=[];
        var j=0;
        var n;
        for(var i=0;i<this.childNodes.length;i++){
            n=this.childNodes[i];
            if(n.nodeType==1){
                tmp[j++]=n;
                if(n.name){
                    if(!tmp[n.name])
                        tmp[n.name]=[];
                    tmp[n.name][tmp[n.name].length]=n;
                    }
                if(n.id)
                    tmp[n.id]=n;
                }
            }
        return tmp;
        });
    HTMLElement.prototype.__defineGetter__("currentStyle", function(){
        return this.ownerDocument.defaultView.getComputedStyle(this,null);
        });
    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;
        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+">";
        });
    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;
        });

    HTMLElement.prototype.__defineSetter__("innerText",function(sText){
        var parsedText=document.createTextNode(sText);
        this.innerHTML=parsedText;
        return parsedText;
        });
    HTMLElement.prototype.__defineGetter__("innerText",function(){
        var r=this.ownerDocument.createRange();
        r.selectNodeContents(this);
        return r.toString();
        });
    HTMLElement.prototype.__defineSetter__("outerText",function(sText){
        var parsedText=document.createTextNode(sText);
        this.outerHTML=parsedText;
        return parsedText;
        });
    HTMLElement.prototype.__defineGetter__("outerText",function(){
        var r=this.ownerDocument.createRange();
        r.selectNodeContents(this);
        return r.toString();
        });
    HTMLElement.prototype.attachEvent=function(sType,fHandler){
        var shortTypeName=sType.replace(/on/,"");
        fHandler._ieEmuEventHandler=function(e){
            window.event=e;
            return fHandler();
            }
        this.addEventListener(shortTypeName,fHandler._ieEmuEventHandler,false);
        }
    HTMLElement.prototype.detachEvent=function(sType,fHandler){
        var shortTypeName=sType.replace(/on/,"");
        if(typeof(fHandler._ieEmuEventHandler)=="function")
            this.removeEventListener(shortTypeName,fHandler._ieEmuEventHandler,false);
        else
            this.removeEventListener(shortTypeName,fHandler,true);
        }
    HTMLElement.prototype.contains=function(Node){// 是否包含某节点
        do if(Node==this)return true;
        while(Node=Node.parentNode);
        return false;
        }
    HTMLElement.prototype.insertAdjacentElement=function(where,parsedNode){
        switch(where){
            case "beforeBegin":
                this.parentNode.insertBefore(parsedNode,this);
                break;
            case "afterBegin":
                this.insertBefore(parsedNode,this.firstChild);
                break;
            case "beforeEnd":
                this.appendChild(parsedNode);
                break;
            case "afterEnd":
                if(this.nextSibling)
                    this.parentNode.insertBefore(parsedNode,this.nextSibling);
                else
                    this.parentNode.appendChild(parsedNode);
                break;
            }
        }
    HTMLElement.prototype.insertAdjacentHTML=function(where,htmlStr){
        var r=this.ownerDocument.createRange();
        r.setStartBefore(this);
        var parsedHTML=r.createContextualFragment(htmlStr);
        this.insertAdjacentElement(where,parsedHTML);
        }
    HTMLElement.prototype.insertAdjacentText=function(where,txtStr){
        var parsedText=document.createTextNode(txtStr);
        this.insertAdjacentElement(where,parsedText);
        }
    HTMLElement.prototype.attachEvent=function(sType,fHandler){
        var shortTypeName=sType.replace(/on/,"");
        fHandler._ieEmuEventHandler=function(e){
            window.event=e;
            return fHandler();
            }
        this.addEventListener(shortTypeName,fHandler._ieEmuEventHandler,false);
        }
    HTMLElement.prototype.detachEvent=function(sType,fHandler){
        var shortTypeName=sType.replace(/on/,"");
        if(typeof(fHandler._ieEmuEventHandler)=="function")
            this.removeEventListener(shortTypeName,fHandler._ieEmuEventHandler,false);
        else
            this.removeEventListener(shortTypeName,fHandler,true);
        }
    }
//-->
</script>

原文链接: http://www.dubox.cn/Trackback.aspx?id=27