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.
HTTP Strict Transport Security (HSTS) informs browsers that the site should only be accessed using HTTPS.
Screenshots with JavaScript.
ASP.NET is an open-source, server-side web-application framework designed for web development to produce dynamic web pages.
YouTube is a video sharing service where users can create their own profile, upload videos, watch, like and comment on other videos.