I have a tabPanel as my base layout.I need to load different local pages on each tabpanel item.i set the autoLoad property with the url to load.but page doesnt get load.

Code:
Ext.setup({
            icon: 'icon.png',
            tabletStartupScreen: 'tablet_startup.png',
            phoneStartupScreen: 'phone_startup.png',
            glossOnIcon: false,
            onReady: function() {
                var tabpanel = new Ext.TabPanel({
                    tabBar: {
                        dock: 'bottom',
                        layout: {
                            pack: 'center'
                        }
                    },
                    fullscreen: true,
                    
                    
                    defaults: {
                        scroll: 'vertical'
                    },
                    items: [{
                        title: 'tab1',
                        autoLoad:{url:'tab1.htm'},
                       listeners:{
                            activate : function(panel){
                            console.log("act"+panel);
                            panel.getUpdater().refresh();
                         }
                      }
                    }, {
                        title: 'tab2',
                        autoLoad:{url:'tab2.htm'},
                        
                    }]
                });
            }
        });

for 'activate' listener in tabpanel item i get the below expection

Uncaught TypeError: Object [object Object] has no method 'getUpdater'.

How could we load the page dynamically?