页面右键菜单Beta2(兼容fw)

//右键菜单js代码开始 
var newX,newY; 
document.onmousedown = function popUp(obj) { 
if(document.all)//判断IE、FireFox 
        menu = document.all.itemopen; 
    else 
        menu = document.getElementById("itemopen"); 
    //if(evt==null) evt=window.event; 
    var evt = obj || window.event; 
if (menu!=null&&evt.button == 2) { 
newX = evt.x?evt.x:evt.pageX + getScrollXY("x"); 
newY = evt.y?evt.y:evt.pageY + getScrollXY("y"); 
     
menu.style.display = ""; 
        if(document.all){ 
        menu.style.pixelLeft = newX; 
        menu.style.pixelTop = newY; 
        }else{ 
            menu.style.left = newX+"px";//ie firefox 
            menu.style.top = newY+"px"; 
        } 
}else if(menu!=null&&evt.button !=2 && (evt.clientX<newX||evt.clientX>(newX+205)||newY>evt.clientY||evt.clientY>(newY+160))){ 
        menu.style.display="none"; 
    } 
    return false; 
} 
function getScrollXY(o){//兼容ie firefox 
    var x,y; 
    if(document.body.scrollTop){ 
        x = document.body.scrollLeft; 
        y = document.body.scrollTop; 
    }else{ 
        x = document.documentElement.scrollLeft; 
        y = document.documentElement.scrollTop; 
    } 
    if(0=="x") 
        return x; 
    else 
        return y; 
} 
function menuClose(){ 
    if(document.all) 
        menu = document.all.itemopen; 
    else 
        menu = document.getElementById("itemopen"); 
    menu.style.display="none"; 
} 
var message=""; 
function clickIE() 
{ 
if (document.all) 
{ 
(message); 
return true; 
}else{ 
        return false; 
    } 
} 
function clickNS(e) 
{ 
if (document.layers||(document.getElementById&&!document.all)) 
{ 
if (e.which==2) 
{ 
newX = window.event.x + document.body.scrollLeft; 
newY = window.event.y + document.body.scrollTop; 
menu = document.all.itemopen; 
if ( menu.style.display == "") 
{ 
menu.style.display = "none"; 
} 
else 
{ 
menu.style.display = ""; 
} 
menu.style.pixelLeft = newX; 
menu.style.pixelTop = newY; 
} 
if (e.which==3) 
{ 
(message); 
return false; 
} 
    } 
} 
if (document.layers) 
{ 
document.captureEvents(Event.MOUSEDOWN); 
document.onmousedown=clickNS; 
} 
else 
{ 
document.onmouseup=clickNS;document.oncontextmenu=clickIE; 
} 
document.oncontextmenu=new Function("return false"); 
//右键菜单js代码结束