Why Use Bootstrap?
Mobile first approach − Bootstrap 3, the framework consists of Mobile first styles throughout the entire library instead them of in separate files.
Browser Support − It is supported by all popular browsers.
Easy to get started − With just the knowledge of HTML and CSS anyone can get started with Bootstrap. Also, the Bootstrap official site has a good documentation.
Responsive design − Bootstrap’s responsive CSS adjusts to Desktops, Tablets, and Mobiles. More about the responsive design is in the chapter Bootstrap Responsive Design.
Provides a clean and uniform solution for building an interface for developers.
It contains beautiful and functional built-in components which are easy to customize.
It also provides web-based customization.
And best of all it is an open source.