cdnjs is a free distributed JS library delivery service.
Flask is a Python micro web framework ideal for rapidly constructing web applications, offering minimalism, flexibility, and modularity.
Google Analytics is a free web analytics service that tracks and reports website traffic.
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.
Python is an interpreted and general-purpose programming language.
reCAPTCHA is a free service from Google that helps protect websites from spam and abuse.