Firstly, AngularJS is free and is used by developers all over since it is open source. Secondly, it provides options of writing client slide application in a Model View Controller way to its developers.
Building large scale web applications which have high performance and maintenance free is one of the core features of AngularJS.
However, there are other core features of AngluarJS that are important, such as:
It is very capable of developing Single Page Applications and provides data binding capacity to HTML. The code of AngularJS is unit testable. It makes use of dependency injection and separation of concerns as well.
The controllers written do the business processing and the software only shows html pages. It also provides you with reusable content. And the most important use of all is that it can be run on any browser and even on smart phones including iOS and Android based phones and tablets.
The AngularJS framework is basically into three parts. The ng-app, ng-model and the ng-bind. The ng-app links the application to HTML and the ng-model binds the data in the application to the HTML input and the ng-bind ties the application data of AngularJS to the HTML tags.