Extjs Treepanel 右键菜单

function createMenu(){     
        //创建一个菜单     
        var myMenu = new Ext.menu.Menu({     
            items:[{     
                text: '右键快捷方式1',     
                menu: [{     
                    text: '右键子菜单1'    
                },{     
                    text: '右键子菜单2'    
                }]     
            },{     
                text: '右键快捷方式2'    
            }]     
        }) ;     
             
        //因为每个树中由N个节点组成的,所以要创建树,必须创建树所包含的节点(树必须有一个或多个根节点).     
        var vRoot = new Ext.tree.TreeNode({text: '根节点1'}) ;//创建节点     
        var vNode1 = new Ext.tree.TreeNode({text: '子节点1'}) ;//创建节点     
        vNode1.appendChild(new Ext.tree.TreeNode({text: '子节点11'}));     
        vNode1.appendChild(new Ext.tree.TreeNode({text: '子节点12'}));     
        var vNode2 = new Ext.tree.TreeNode({text: '子节点1'}) ;//创建节点     
        vRoot.appendChild(vNode1) ;//在vRoot根节点上创建子节点.     
        vRoot.appendChild(vNode2) ;//在vRoot根节点上创建子节点.     
             
        var obj = {     
            title: '我的Menu练习',     
            renderTo: document.body,     
            height: 300,     
            width: 600,     
            root: vRoot,     
            tbar:[{     
                text: '文件',     
                menu: {items:[{     
                    text: '打开',     
                    icon: '../images/open.gif'    
                },{     
                    text: '保存',     
                    icon: '../images/save.gif'    
                },'-',{     
                    text: '另存为...',     
                    handler: function(b){     
                        var win = new Ext.Window({     
                            title: '另存为对话框',     
                            width: 200,     
                            height: 200,     
                            html: '可以在此处进行其他操作'    
                        });     
                        win.show() ;     
                    }     
                }]}     
            },'-',{//在两个按钮之间添加一条分隔线     
                text: '编辑'    
            },'->',{//右顶格显示'帮助'按钮     
                text: '帮助'    
            }],     
            listeners: {//添加监听器,实现右键Tree显示定义菜单myMenu     
                contextmenu: function(n,e){     
                    myMenu.showAt(e.getXY()) ;     
                }     
            }     
        };     
        var myPanel = new Ext.tree.TreePanel(obj) ;     
    }     
    Ext.onReady(createMenu);//创建动态树