Bootstrap Code Play

Bootstrap is the most popular free front-end framework for faster and easier web development. Its includes HTML and CSS based design templates for typography, forms, buttons, tables, navigation, modals, image carousels and many other, as well as optional JavaScript plugins.

It also gives you the ability to easily create responsive, mobile-first projects on the web. It's made for folks of all skill levels, devices of all shapes, and projects of all sizes.

Bootstrap is a front-end framework, that is, an interface for the user, unlike the server-side code which resides on the "back end" or server.