AngularsJS is structural open source framework for single page dynamic applications and developed by Google. Its simplify the developing and testing such as a application by providing framework for client side Model View Controller(MVC) architecture along with components commonly used in RIA(Rich Internet Applications).
It lets you use HTML as your template language and lets you extend HTML's syntax to express your application's components clearly and succinctly. Angular's data binding and dependency injection eliminate much of the code you would otherwise have to write. And it all happens within the browser, making it an ideal partner with any server technology.
Simple just go to AngularJs official(https://angularjs.org/) website, you will see 2 tabs one is GitHub and another one is Download (it allow you to download the files directly from the google server), download the files include in the application. play with angularJs create single page application