cdnjs is a free distributed JS library delivery service.
Chosen is a jQuery plugin that makes long, unwieldy select boxes much more user-friendly.
Google Hosted Libraries is a stable, reliable, high-speed, globally available content distribution network for the most popular, open-source JavaScript libraries.
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.
LiteSpeed is a high-scalability web server.
PHP is a general-purpose scripting language used for web development.
Pure CSS is a set of small, responsive CSS modules that can be used in web projects.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.