jquery - Dropdown doesnt refresh in angular js -

i have 2 drop downs when select first drop down second drop down should load based on selection. doing in angular js. used watch event load drop down event

angular.module('myapp', ['']).controller('qmesaures', function ($scope) {   $scope.$watch('ddldepartment', function (newval) {             var departmentname = newval.departmentname           $.ajax({                 type: "post",                  data: json.stringify({ departmentname: departmentname }),                 url: "/qreport/getproviders",                 contenttype: "application/json; charset=utf-8",                 success: function (data) {                    alert(data);                     $scope.$apply(function () {                         $scope.providers = data;                      });                   }             });          });  });    <div ng-app="myapp" ng-controller="qmesaures"> <select  ng-model="ddlproviders" ng-options="provider.providername provider in providers"></select> </div> 

but problem getting data able see alert box second dropdown (provider drop down) doesnt show value.

please me how refresh dropdown show values in angular js.

you have watcher on variable doesn't exist on scope far can tell. $scope.ddldepartment undefined code have shown.