Bootstrap is the most popular HTML, CSS, and JS framework for developing responsive, mobile first projects on the web.
Bootstrap is a great and free open-source front-end web framework for use in websites and web applications. It uses HTML and CSS and only concerns itself in front-end development! It is so popular that even on Github.com it is the second most "starred" project!
It is compatible with all popular browsers including:
Did you know?
Bootstrap used to be called Twitter Blueprint!