AngularJS Controller

AngularJS Controller controls the data of AngularJS applications. AngularJS Controllers are regular JavaScript Objects.

AngularJS Controller

AngularJS applications are controlled by controllers. The ng-controller directive defines the application controller. A controller is a JavaScript Object, created by a standard JavaScript object constructor.

AngularJS Example

<div ng-app="myApp" ng-controller="myCtrl">
    First Name: <input type="text" ng-model="firstName"><br>
    Last Name: <input type="text" ng-model="lastName"><br><br>
    Full Name: {{firstName + " " + lastName}}
</div>
<script>
var app = angular.module('myApp', []);
app.controller('myCtrl', function($scope) {
    $scope.firstName = "John";
    $scope.lastName = "Doe";
});
</script>

Application Explained:

The AngularJS application is defined by ng-app. The application runs inside the <div>. The ng-controller="myCtrl" attribute is an AngularJS directive. It defines a controller. The myCtrl function is a JavaScript function. AngularJS will invoke the controller with a $scope object. In AngularJS, $scope is an application object (contains application variables and functions). The controller creates two properties (variables) in the scope (firstName and lastName). The ng-model directive binds the input fields to the controller properties (firstName and lastName).

Controller Methods

The example above demonstrates a controller object with two properties: lastName and firstName. A controller can also have methods (variables and functions):

AngularJS Example

<div ng-app="myApp" ng-controller="personCtrl">
    First Name: <input type="text" ng-model="firstName"><br>
    Last Name: <input type="text" ng-model="lastName"><br>
    <br>
    Full Name: {{fullName()}}
</div>
<script>
var app = angular.module('myApp', []);
app.controller('personCtrl', function($scope) {
    $scope.firstName = "John";
    $scope.lastName = "Doe";
    $scope.fullName = function() {
        return $scope.firstName + " " + $scope.lastName;
    };
});
</script>

Controllers in External Files

In large applications, it is common to store controllers in external files. Simply copy the code between the <script> tags into an external file named personController.js:

AngularJS Example

<div ng-app="myApp" ng-controller="personCtrl">
    First Name: <input type="text" ng-model="firstName"><br>
    Last Name: <input type="text" ng-model="lastName"><br><br>
    Full Name: {{firstName + " " + lastName}}
</div>
<script src="personController.js"></script>

Other Examples

The following example creates a new controller file:

angular.module('myApp', []).controller('namesCtrl', function($scope) {
    $scope.names = [
        {name:'Jani',country:'Norway'},
        {name:'Hege',country:'Sweden'},
        {name:'Kai',country:'Denmark'}
    ];
});

Save the file as namesController.js:

Then, use the controller file in the application:

AngularJS Example

<div ng-app="myApp" ng-controller="namesCtrl">
<ul>
  <li ng-repeat="x in names">
      {{ x.name + ', ' + x.country }}
  </li>
</ul>
</div>
<script src="namesController.js"></script>