Angular JS

AngularJS is a structural framework for dynamic web apps. 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.
Angular is what HTML would have been, had it been designed for applications. HTML is a great declarative language for static documents. It does not contain much in the way of creating applications, and as a result building web applications is an exercise in what do I have to do to trick the browser into doing what I want?
The impedance mismatch between dynamic applications and static documents is often solved with:

• a library – a collection of functions which are useful when writing web apps. Your code is in charge and it calls into the library when it sees fit. E.g., jQuery.
• frameworks – a particular implementation of a web application, where your code fills in the details. The framework is in charge and it calls into your code when it needs something app specific. E.g., durandal, ember, etc.

AngularJS is based on the MVC pattern (Model View Control). Therefore AngularJS separates your RIA (Rich internet Application) application into models, views and controllers. The views are specified using HTML + AngularJS’s own template language. The models and controllers are specified via JavaScript objects and JavaScript functions. Thus, the views are specified declaratively, as HTML normally is, and the models and controllers are specified imperatively, as JavaScript normally is.
Angular takes another approach. It attempts to minimize the impedance mismatch between document centric HTML and what an application needs by creating new HTML constructs. Angular teaches the browser new syntax through a construct we call directives. Examples include:

• Data binding, as in {{}}.
• DOM control structures for repeating, showing and hiding DOM fragments.
• Support for forms and form validation.
• Attaching new behavior to DOM elements, such as DOM event handling.
• Grouping of HTML into reusable components.

The Document Object Model (DOM) is a programming interface for HTML, XML and SVG documents. It provides a structured representation of the document (a tree) and it defines a way that the structure can be accessed from programs so that they can change the document structure, style and content.