js应该如何编写右击事件

我想实现鼠标右击时，触发某个事件.
应该怎么做呢，求具体代码！

非常简洁高效的JS右键菜单

在制作网页的时候,我们很经常需要用到右键菜单,网上这类的控件很多,很眩. 但这类控件一般都比较大,需要写的代码比较多,而且样式比较固定. 而本组件相对简单高效, 定制性很强, 菜单全由自己DIY!

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);

}

=======================需要显示的菜单,一般用DIV======================

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============================调用方法===============================

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

其中, document.getElementById("Table1") 就是需要显示菜单的区域控件.
document.getElementById("Menu1") 就是菜单DIV控件.

 document.getElementById("test").onmouseup=function(oEvent) {
    if (!oEvent) oEvent=window.event;
    if (oEvent.button==2) {
        //-- do something for user right click
        // alert("Mouse up");
    }
}


<script>
    document.oncontextmenu = function () { alert('按下右键！'); }
</script>

 <html>  
<script type="text/javascript">  
 <!--  
    document.onmousedown = function(e){  
        var e = e || window.event  
        alert("e"+e.button);  
        if(e.button == "2"){  
            alert("执行右键代码");  
        }  
    }  
 //-->  
 function right()  
 {  

        var e=window.event;  
        alert(e.button);  
        if(e.button=="0"){  
            alert("左键");  
        }else{  
            alert("右键");  
        }  
 }  
 </script>  



<table border=1>  
<tr id=test name=test height=200  onmousedown="right()" ><td>88888888888888888888888888</td></tr>  
</table>  

</html>

下面是运行效果：
图片说明

编写右击事件一般可分为一下几步：
一、捕获，捕获右击事件很简单，楼上的同仁都已做了清楚的回答；
二、阻止默认右击事件，浏览器默认的会为右击事件做出响应，即我们点击右键时看到的菜单，要想対右键点击事件做出明确的响应，这一步是非常重要的一步；
三、编写自己的处理逻辑；