ext checkboxgroup 取值

Ext.onReady(function(){
            var myCheckboxGroup = new
 Ext.form.CheckboxGroup({
                id:'myGroup'
,
                xtype: 'checkboxgroup'
,
                renderTo :'form-cb'
,
                fieldLabel: 'Single Column'
,
                itemCls: 'x-check-group-alt'
,
                columns: 3
,
                items: [
                    {boxLabel: '唱歌'
, name: 
'1'
},
                    {boxLabel: '游泳'
, name: 
'2'
, checked: 
true
},
                    {boxLabel: '看书'
, name: 
'3'
},
                    {boxLabel: '旅游'
, name: 
'4'
},
                    {boxLabel: '游戏'
, name: 
'5'
},
                    {boxLabel: '睡觉'
, name: 
'6'
}
                ]
            });

            //CheckboxGroup取值方法
            for
 (var i = 
0
; i < myCheckboxGroup.items.length; i++)
            {
                if
 (myCheckboxGroup.items.itemAt(i).checked)
                {
                    alert(myCheckboxGroup.items.itemAt(i).name);
                }
            }
        });