Prof. Tushar Gohil

Scopes

Scope is a special JavaScript object that connects controller with views. Scope contains model data. In controllers, model data is accessed via $scope object.

<script>
   var mainApp = angular.module("mainApp", []);
   
   mainApp.controller("shapeController", function($scope) {
      $scope.message = "In shape controller";
      $scope.type = "Shape";
   });
</script>

The following important points are considered in above example −

The $scope is passed as first argument to controller during its constructor definition.
The $scope.message and $scope.type are the models which are used in the HTML page.
We assign values to models that are reflected in the application module, whose controller is shapeController.
We can define functions in $scope.

Scope Inheritance

Scope is controller-specific. If we define nested controllers, then the child controller inherits the scope of its parent controller.

<script>
   var mainApp = angular.module("mainApp", []);
   
   mainApp.controller("shapeController", function($scope) {
      $scope.message = "In shape controller";
      $scope.type = "Shape";
   });
   mainApp.controller("circleController", function($scope) {
      $scope.message = "In circle controller";
   });
	
</script>

The following important points are considered in above example −

We assign values to the models in shapeController.
We override message in child controller named circleController. When message is used within the module of controller named circleController, the overridden message is used.

Example

The following example shows use of all the above mentioned directives.

testAngularJS.htm

<html>
   <head>
      <title>Angular JS Forms</title>
   </head>
   
   <body>
      <h2>AngularJS Sample Application</h2>
      
      <div ng-app = "mainApp" ng-controller = "shapeController">
         <p>{{message}} <br/> {{type}} </p>
         
         <div ng-controller = "circleController">
            <p>{{message}} <br/> {{type}} </p>
         </div>
         
         <div ng-controller = "squareController">
            <p>{{message}} <br/> {{type}} </p>
         </div>
			
      </div>
      <script src = "https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js">
      </script>
      
      <script>
         var mainApp = angular.module("mainApp", []);
         
         mainApp.controller("shapeController", function($scope) {
            $scope.message = "In shape controller";
            $scope.type = "Shape";
         });
         mainApp.controller("circleController", function($scope) {
            $scope.message = "In circle controller";
         });
         mainApp.controller("squareController", function($scope) {
            $scope.message = "In square controller";
            $scope.type = "Square";
         });
			
      </script>
      
   </body>
</html>

Live Demo

Output

Open the file testAngularJS.htm in a web browser and see the result.

Root Scope

All applications have a $rootScope which is the scope created on the HTML element that contains the ng-app directive.

The rootScope is available in the entire application.

If a variable has the same name in both the current scope and in the rootScope, the application uses the one in the current scope.

Advanced Web Programming

Curriculum