jQuery UI is a collection of GUI widgets, animated visual effects, and themes implemented with jQuery, Cascading Style Sheets, and HTML.
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.
Ruby is an open-source object-oriented programming language.
WEBrick is a lightweight HTTP server library in Ruby, included in the standard library, primarily used for local development and testing of Ruby web applications.