Why Angular JS?

Interactive Web Application

• HTML and CSS are not interactive. You cannot create interactive applications using HTML and CSS.
• JavaScript allows you to interact with a web page like clicking a button, validate form data, resize window etc.

HTML 5 + CSS 3 + JavaScript = Interactive Web Application

Rich Internet Application- RIA

• RIA (Rich Internet Applications) are a special breed of web applications where the user interface has much richer functionality.
• RIA user interfaces are typically developed using HTML5 + JavaScript + CSS3, Flex (Flash).+ Angular JS + Bootstrap + JQuery

JavaScript Frameworks

There are lot of JavaScript frameworks available in market.

• Ember JS
• Backbone JS
• Knockout JS
• React JS

Need for Angular JS

• Modular Development (Service, Controllers, Routers etc)
• Reusable Components (Directives)
• Two way data binding
• Unit Testing frameworks 
• Client Requirement