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:

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 Directives

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

AngularJS Expressions

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

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.