phonegap返回键等设置

<pre><script type= "text/javascript" charset= "utf-8" >
     document.addEventListener( "deviceready" , onDeviceReady, false );
     // PhoneGap加载完毕
     function onDeviceReady() {
         //按钮事件
         checkConnection();
         document.addEventListener( "backbutton" , eventBackButton, false ); //返回键
         document.addEventListener( "menubutton" , eventMenuButton, false ); //菜单键
         document.addEventListener( "searchbutton" , eventSearchButton, false ); //搜索键
 
     }
     function onConfirm(button) {
 
         if (button == '1' ) {
 
             navigator.app.exitApp();
         } else {
 
         }
 
     }
     //返回键
     function eventBackButton() {
         navigator.notification.confirm( '确定退出cfxxi？' , // 显示信息
         onConfirm, // 按下按钮后触发的回调函数，返回按下按钮的索引
         '退出应用' , // 标题
         '确定,取消' // 按钮标签
         );
 
     }
     //菜单键
     function eventMenuButton() {
         //alert('点击了 菜单 按钮!');
     }
 
     //搜索键
     function eventSearchButton() {
 
         //window.plugins.ToastPlugin.show_short('点击了 搜索 按钮!');
     }
 
     function checkConnection() {
         var networkState = navigator.network.connection.type;       
 
         var states = {};
         states[Connection.UNKNOWN]  = 'Unknown connection' ;
         states[Connection.ETHERNET] = 'Ethernet connection' ;
         states[Connection.WIFI]     = 'WiFi connection' ;
         states[Connection.CELL_2G]  = 'Cell 2G connection' ;
         states[Connection.CELL_3G]  = 'Cell 3G connection' ;
         states[Connection.CELL_4G]  = 'Cell 4G connection' ;
         states[Connection.NONE]     = 'No network connection' ;
         //alert(states[networkState]);
         if (states[networkState]== 'No network connection' || typeof states[networkState] == "undefined" )
         {
 
             Ext.Msg.alert( '警告' , '应用需要连接网络获得数据，请打开网络.' , function (){
                 navigator.device.exitApp();
             });
         }
     };
</script></pre>