function Menu(menu){   
    this.isIE = !!(window.attachEvent &&navigator.userAgent.indexOf('Opera') === -1);//ÅжÏÊÇ·ñÊÇIE   
    this.y = function(e){   
        var offset=e.offsetTop;   
        if(e.offsetParent!=null) offset+=this.y(e.offsetParent);   
        return offset;   
    }   
    this.x = function(e){   
        var offset=e.offsetLeft;   
        if(e.offsetParent!=null) offset+=this.x(e.offsetParent);   
        return offset;   
    }   
    this.$ = function(id){   
        return document.getElementById(id);   
    }   
    this.$$ = function(obj,name){   
        var rs = new Array();   
        var childNodes = obj.childNodes;   
        for(var i = 0 ;i<childNodes.length;i++){   
            if(childNodes[i].nodeName == name){   
                rs.push(childNodes[i]);   
            }   
        }   
        return rs;   
    }   
    this.root = this.$(menu);   
    this.init();   
}   
Menu.prototype.init = function(){   
    this.bind(this.root);   
}   
Menu.prototype.bind = function(root){   
    var liNodes = this.$$(root,'LI');   
    for(var i = 0;i<liNodes.length;i++){   
        var liNode = liNodes[i];   
        if(liNode.style.display==''||liNode.style.display=='none'){   
            if(this.isIE){   
                liNode.style.display = 'inline';   
            }   
            else {   
                liNode.style.display = 'inline-block';   
            }   
        }   
        var divs = this.$$(liNode,'DIV');   
        for(var j=0;j<divs.length;j++){   
            var div = divs[j];   
            div.style.display = 'none';   
            if(div.style.width==''){   
                div.style.maxWidth = this.root.style.width;   
            }   
            div.style.position = 'absolute';   
            if(this.isIE){   
                div.style.left = this.x(liNode);   
                div.style.top = this.y(liNode) + liNode.offsetHeight;   
            }   
               
            var uls = this.$$(div,'UL');   
            for(var  k =0;k<uls.length;k++){   
                this.bind(uls[k]);   
            }   
        }   
        liNode.$$ = function(name){   
            var rs = new Array();   
            var childNodes = this.childNodes;   
            for(var i = 0 ;i<childNodes.length;i++){   
                if(childNodes[i].nodeName == name){   
                    rs.push(childNodes[i]);   
                }   
            }   
            return rs;   
        }   
        liNode.onmouseover = function (){   
            var ds = this.$$('DIV');   
            for(var j=0;j<ds.length;j++){   
                var div = ds[j];   
                div.style.display = 'block';   
            }   
        }   
        liNode.onmouseout = function (){   
            var ds = this.$$('DIV');   
            for(var j=0;j<ds.length;j++){   
                var div = ds[j];   
                div.style.display = 'none';   
            }   
        }   
    }   
}