AngularJS Application

It is time to create a real AngularJS Single Page Application (SPA).

An AngularJS Application Example

You have learned more than enough to create your first AngularJS application:

My Note

Number of characters left:

Application Explained

AngularJS Example

<html ng-app="myNoteApp">
<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>

<div ng-controller="myNoteCtrl">

<h2>My Note</h2>

<p><textarea ng-model="message" cols="40" rows="10"></textarea></p>

<button ng-click="save()">Save</button>
<button ng-click="clear()">Clear</button>

<p>Number of characters left: <span ng-bind="left()"></span></p>


<script src="myNoteApp.js"></script>
<script src="myNoteCtrl.js"></script>

Try it Yourself »

The application file "myNoteApp.js":

var app = angular.module("myNoteApp", []);

The controller file "myNoteCtrl.js":

app.controller("myNoteCtrl", function($scope) {
    $scope.message = "";
    $scope.left  = function() {return 100 - $scope.message.length;};
    $scope.clear = function() {$scope.message = "";};
    $scope.save  = function() {alert("Note Saved");};

The <html> element is the container of the AngularJS application: ng-app="myNoteApp":

<html ng-app="myNoteApp">

A a <div> in the HTML page is the scope of a controller: ng-controller="myNoteCtrl":

<div ng-controller="myNoteCtrl">

An ng-model directive binds a <textarea> to the controller variable message:

<textarea ng-model="message" cols="40" rows="10"></textarea>

The two ng-click events invoke the controller functions clear() and save():

<button ng-click="save()">Save</button>
<button ng-click="clear()">Clear</button>

An ng-bind directive binds the controller function left() to a <span> displaying the characters left:

Number of characters left: <span ng-bind="left()"></span>

Your application libraries are added to the page (after the library):

<script src="myNoteApp.js"></script>
<script src="myNoteCtrl.js"></script>

AngularJS Application Skeleton

Above you have the skeleton (scaffolding) of a real life AngularJS, single page application (SPA).

The <html> element is the "container" for the AngularJS application (ng-app=).

A <div> elements defines the scope of an AngularJS controller (ng-controller=).

You can have many controllers in one application.

An application file (my...App.js) defines the application module code.

One or more controller files (my...Ctrl.js) defines the controller code.

Summary - How Does it Work?

The ng-app directive is placed at the root element of the application.

For single page applications (SPA), the root of the application is often the <html> element.

One or more ng-controller directives define the application controllers. Each controller has its own scope: the HTML element where they were defined.

AngularJS starts automatically on the HTML DOMContentLoaded event. If an ng-app directive is found, AngularJS will load any module named in the directive, and compile the DOM with ng-app as the root of the application.

The root of the application can be the whole page, or a smaller portion of the page. The smaller the portion, the faster the application will compile and execute.