Apache is a free and open-source cross-platform web server software.
cdnjs is a free distributed JS library delivery service.
Contao is an open source CMS that allows you to create websites and scalable web applications.
jQuery plugin for seeing if the images are loaded.
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.
PHP is a general-purpose scripting language used for web development.