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AngularJS Introduction


AngularJS is a JavaScript framework. It can be added to an HTML page with a <script> tag.

AngularJS extends HTML attributes with Directives, and binds data to HTML with Expressions.


AngularJS is a JavaScript Framework

AngularJS is a JavaScript framework. It is a library written in JavaScript.

AngularJS is distributed as a JavaScript file, and can be added to a web page with a script tag:

<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>

AngularJS Extends HTML

AngularJS extends HTML with ng-directives.

The ng-app directive defines an AngularJS application.

The ng-model directive binds the value of HTML controls (input, select, textarea) to application data.

The ng-bind directive binds application data to the HTML view.

AngularJS Example

<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
<body>

<div ng-app="">
  <p>Name: <input type="text" ng-model="name"></p>
  <p ng-bind="name"></p>
</div>

</body>
</html>

Try it Yourself »

Example explained:

AngularJS starts automatically when the web page has loaded.

The ng-app directive tells AngularJS that the <div> element is the "owner" of an AngularJS application.

The ng-model directive binds the value of the input field to the application variable name.

The ng-bind directive binds the innerHTML of the <p> element to the application variable name.


AngularJS Directives

As you have already seen, AngularJS directives are HTML attributes with an ng prefix.

The ng-init directive initialize AngularJS application variables.

AngularJS Example

<div ng-app="" ng-init="firstName='John'">

<p>The name is <span ng-bind="firstName"></span></p>

</div>

Try it Yourself »

Alternatively with valid HTML:

AngularJS Example

<div data-ng-app="" data-ng-init="firstName='John'">

<p>The name is <span data-ng-bind="firstName"></span></p>

</div>

Try it Yourself »
Note You can use data-ng-, instead of ng-, if you want to make your page HTML valid.

You will learn a lot more about directives later in this tutorial.


AngularJS Expressions

AngularJS expressions are written inside double braces: {{ expression }}.

AngularJS will "output" data exactly where the expression is written:

AngularJS Example

<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
<body>

<div ng-app="">
  <p>My first expression: {{ 5 + 5 }}</p>
</div>

</body>
</html>

Try it Yourself »

AngularJS expressions bind AngularJS data to HTML the same way as the ng-bind directive.

AngularJS Example

<!DOCTYPE html>
<html>
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
<body>

<div ng-app="">
  <p>Name: <input type="text" ng-model="name"></p>
  <p>{{name}}</p>
</div>

</body>
</html>

Try it Yourself »

You will learn more about expressions later in this tutorial.


AngularJS Applications

AngularJS modules define AngularJS applications.

AngularJS controllers control AngularJS applications.

The ng-app directive defines the application, the ng-controller directive defines the controller.

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>

Try it Yourself »

AngularJS modules define applications:

AngularJS Module

var app = angular.module('myApp', []);

AngularJS controllers control applications:

AngularJS Controller

app.controller('myCtrl', function($scope) {
    $scope.firstName= "John";
    $scope.lastName= "Doe";
});

You will learn more about modules and controllers later in this tutorial.



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