angular js 引入第三方插件，$scope.$watch 失效，请问如何解决，小白求大神带

  $scope.$watch('myKw',
              function (newValue,oldValue) {
                  console.log($scope.myKw)   //拿不到值 
                  if($scope.myKw.length>0)
                  {
                      $http.get(
                          'data/dish_getbykw.php?kw='
                          +$scope.myKw)
                          .success(function (data) {}

引入的是一个页面锚点跳转的angular插件

 app.controller('scrollCtrl', function($scope, $document){
        $scope.toTheTop = function() {
            $document.scrollTopAnimated(0, 3000).then(function() {
                console.log('You just scrolled to the top!');
            });
        };
    }

在值改变的地方加上$scope.$apply嘞？

  $scope.$apply(function(){
            $scope.$watch('myKw',
                function (newValue,oldValue) {
                    $scope.hasMore=false;
                    console.log($scope.myKw)