求一简单的EXT刷新功能

var tab=new Ext.TabPanel({animate:true,autoTabs:true,resizeTabs:true
listeners:{
"contextmenu":function(tdemo,myitem,e){
                    menu=new Ext.menu.Menu([{
                             text:"关闭当前页",
                             handler:function(){
                                tdemo.remove(myitem);
                             }
                    },{
                             text:"刷新当前页",
                             handler:function(){
                             //这里写什么能刷新当前页？
                             ................
                       }
                    }]);
                    //显示在当前位置
                    menu.showAt(e.getPoint());
         }
}