Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
cdnjs is a free distributed JS library delivery service.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
JSDelivr is a free public CDN for open-source projects. It can serve web files directly from the npm registry and GitHub repositories without any configuration.
MDBootstrap (Material Design for Bootstrap) is a complete UI package that can be integrated with other frameworks such as Angular, React, Vue, etc. It is used to design a fully responsive and mobile-friendly layout using various components, plugins, animation.
OpenResty is a web platform based on nginx which can run Lua scripts using its LuaJIT engine.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.