一個非常簡潔高效的JS右鍵菜單!

function csMenu(_object, _menu)
{
    this.IEventHander = null;
    this.IFrameHander = null;
    this.IContextMenuHander = null;

    this.Show = function(_menu)
    {
        var e = window.event || event;
        if (e.button == 2)
        {
            if (window.document.all)
            {
                this.IContextMenuHander = function(){return false;};
                document.attachEvent("oncontextmenu", this.IContextMenuHander);
            }
            else
            {
                this.IContextMenuHander = document.oncontextmenu;
                document.oncontextmenu = function(){return false;};
            }

            window.csMenu$Object = this;
            this.IEventHander = function(){window.csMenu$Object.Hide(_menu);};

            if (window.document.all)
                document.attachEvent("onmousedown", this.IEventHander);
            else
                document.addEventListener("mousedown", this.IEventHander, false);

            _menu.style.left = e.clientX;
            _menu.style.top = e.clientY;
            _menu.style.display = "";
            
            if (this.IFrameHander)
            {
                var _iframe = document.getElementById(this.IFrameHander);
                _iframe.style.left = e.clientX;
                _iframe.style.top = e.clientY;
                _iframe.style.height = _menu.offsetHeight;
                _iframe.style.width = _menu.offsetWidth;
                _iframe.style.display = "";
            }
        }
    };

    this.Hide = function(_menu)
    {
        var e = window.event || event;
        var _element = e.srcElement;
        do
        {
            if (_element == _menu)
            {
                return false;
            }
        }
        while ((_element = _element.offsetParent));
        
        if (window.document.all)
    	    document.detachEvent("on"+e.type, this.IEventHander);
        else
    	    document.removeEventListener(e.type, this.IEventHander, false);
        
        if (this.IFrameHander)
        {
            var _iframe = document.getElementById(this.IFrameHander);
            _iframe.style.display = "none";
        }
        
        _menu.style.display = "none";
        
        if (window.document.all)
    	    document.detachEvent("oncontextmenu", this.IContextMenuHander);
        else
    	    document.oncontextmenu = this.IContextMenuHander;
    };

    this.initialize = function(_object, _menu)
    {  
        window._csMenu$Object = this;
        var _eventHander = function(){window._csMenu$Object.Show(_menu);};

        _menu.style.position = "absolute";
	    _menu.style.display = "none";
	    _menu.style.zIndex = "1000000";
	    
        if (window.document.all)
        {
            var _iframe = document.createElement('iframe');
	    document.body.insertBefore(_iframe, document.body.firstChild);
            _iframe.id = _menu.id + "_iframe";
            this.IFrameHander = _iframe.id;

            _iframe.style.position = "absolute";
            _iframe.style.display = "none";
            _iframe.style.zIndex = "999999";
            _iframe.style.border = "0px";
            _iframe.style.height = "0px";
            _iframe.style.width = "0px";
            
            _object.attachEvent("onmouseup", _eventHander);
        }
        else
        {
            _object.addEventListener("mouseup", _eventHander, false);
        }
    };

    this.initialize(_object, _menu);
}

=======================需要顯示的菜單,一般用DIV======================
<div id="Menu1" style="background-color:White; border:1px solid #cccccc; padding:10px;">
    <li>打開</li>
    <li>打印</li>
    <li>回覆發件人</li>
    <li>全部回覆</li>
    <li>轉發</li>
    <li>分配</li>
    <li>垃圾郵件</li>
    <li>刪除</li>
    <li>歸檔此郵件</li>
    <li>分揀此郵件</li>
</div>

============================調用方法===============================

var MM = new csMenu(document.getElementById("Table1"), document.getElementById("Menu1"));

其中, document.getElementById("Table1") 就是需要顯示菜單的區域控件.
      document.getElementById("Menu1") 就是菜單DIV控件.