angularjs实现省份城市的级联绑定问题

页面

                                    <select class="sl" name="province_code" id="province_code" ng-model="provincecode" ng-change="getAreaByCode(provincecode)">
                                        <option value="" selected>请选择</option>
                                        <option ng-selected="p.code==provincecode" value="{{p.code}}"  ng-repeat="p in provinces">{{p.areaName}}</option>
                                    </select>
                                    <select class="sl" name="city_code" id="city_code" ng-model="citycode">
                                        <option value="" selected>请选择</option>
                                        <option ng-selected="c.code==citycode" value="{{c.code}}"  ng-repeat="c in citys">{{c.areaName}}</option>
                                    </select><span style="color:red">*</span>
                                </td>
                            </tr>

controller:
$scope.updateGroup = function(id,ismanager){
$scope.showmanager = ismanager;
console.log(id);
Http.request({
url: Util.ajax.selectAllById(id),
data: {type:$scope.wxtype,
id:id},
success: function (res) {
//res.wechatInfo.createtime = Util.formatDate(res.wechatInfo.createtim,"yyyy-MM-dd hh:mm:ss");
$scope.userInfo = res.wechatInfo;
// $scope.name=res.wechatInfo.name;
// $scope.introduction = res.wechatInfo.introduction;
// $scope.tag = res.wechatInfo.tag;
// $scope.wechatnumber = res.wechatInfo.wechatnumber;
// $scope.linkman = res.wechatInfo.linkman;
// $scope.linkmantel = res.wechatInfo.linkmantel;
// $scope.linkmanqq = res.wechatInfo.linkmanqq;
// $scope.provincecode = res.wechatInfo.provincecode;
$scope.industryid = res.wechatInfo.industryId;
$scope.image_icon = res.wechatInfo.headImg;
$scope.image_qrcode = res.wechatInfo.qrcodeImg;
$scope.image_wx_qrcode = res.wechatInfo.groupQrCodeImg;
$scope.provincecode = res.wechatInfo.provinceCode;
$scope.citycode = res.wechatInfo.cityCode;
console.log(res.wechatInfo);
}

页面

请选择
{{p.areaName}}


请选择
{{c.areaName}}
*

页面问题：省份绑定了 城市没有级联绑定