extjs ComboBox联动下拉菜单示例

        var provinces = [[1,'北京'],[2,'上海']];
        var cities = new Array();
        cities[1] = [[11,'海淀'],[22,'东城']];
        cities[2] = [[33,'黄埔'],[44,'浦东'],[55,'静安']];
        var comboProvinces = new Ext.form.ComboBox({
        store: new Ext.data.SimpleStore( {
        fields: ["provinceId", "provinceName"],
        data: provinces
        }),
        listeners:{
        select:function(combo, record,index){
        comboCities.clearValue();
        comboCities.store.loadData(cities[record.data.provinceId]);
        }
        },
        valueField :"provinceId",
        displayField: "provinceName",
        mode: 'local',
        forceSelection: true,
        blankText:'请选择省份',
        emptyText:'请选择省份',
        hiddenName:'provinceId',
        editable: false,
        triggerAction: 'all',
        allowBlank:true,
        fieldLabel: '请选择省份',
        name: 'provinceId',
        width: 80
        });
        var comboCities = new Ext.form.ComboBox({
        store: new Ext.data.SimpleStore( {
        fields: ["cityId",'cityName'],
        data:[]
        }),
        valueField :"cityId",
        displayField: "cityName",
        mode: 'local',
        forceSelection: true,
        blankText:'选择地区',
        emptyText:'选择地区',
        hiddenName:'cityId',
        editable: false,
        triggerAction: 'all',
        allowBlank:true,
        fieldLabel: '选择地区',
        name: 'cityId',
        width: 80
        });