Posted By : Shailendra Chauhan, 10 Sep 2014
Updated On : 29 Dec 2014
Scope is an object that refers to the application model. It acts as a context for evaluating expressions. Typically, it acts as a glue between controller and view. Scopes are hierarchical in nature and follow the DOM structure of your angular app. AngularJS has two scope objects: $rootScope and $scope. Let's have a look, how they work.
$scope
A $scope is a JavaScript object which is used for communication between controller and view. Basically, $scope binds a view (DOM element) to the viewmodel and functions defined in a controller.
$rootScope
The $rootScope is the top-most scope. An app can have only one $rootScope which will be shared among all the components of an app. Hence it acts like a global variable. All other $scopes are children of the $rootScope.
AngularJS : $rootScope and $scope with example
<!doctype html>
<html>
<body ng-app="myApp">
<div ng-controller="Ctrl1" style="border:2px solid blue; padding:5px">
Hello {{msg}}!
<br />
Hello {{name}}!
(rootScope)
</div>
<br />
<div ng-controller="Ctrl2" style="border:2px solid green; padding:5px">
Hello {{msg}}!
<br />
Hey {{myName}}!
<br />
Hi {{name}}! (rootScope)
</div>
<script src="lib/angular.js"></script>
<script>
var app = angular.module('myApp', []);
app.controller('Ctrl1', function ($scope, $rootScope) {
$scope.msg = 'World';
$rootScope.name = 'AngularJS';
});
app.controller('Ctrl2', function ($scope, $rootScope) {
$scope.msg = 'Dot Net Tricks';
$scope.myName = $rootScope.name;
});
</script>
</body>
</html>
How it works...
Note
When you use ng-model with $rootScope objects then AngularJS updates those objects under a specific $scope of a controller but not at global level $rootScope.
Create a private $scope for each controller to bind it to the view.
What do you think?
I hope you will enjoy the AngularJS: $rootScope and $scope while developing your app with AngularJS. I would like to have feedback from my blog readers. Your valuable feedback, question, or comments about this article are always welcome.
