Available YUI Downloads

YUI Build Tool

YUI Builder contains the component build tool, which is the ANT based build system YUI uses to generate the code in the YUI 2 and YUI 3 build directories, from the contents of the src directories for each component.

YUI PHP Loader

The YUI PHP Loader is a server-side utility that can be used for loading YUI components and their dependencies via PHP. This utility is comparable to the YUI Loader, a client side loader that provides similar functionality in Javascript.


YUI Library is a set of utilities and controls written in JavaScript, for building richly interactive web applications. YUI 2 is a mature version of the library that has been in production since 2006. The code line is comprised of a comprehensive collection of over 30 utilities and widgets.


YUI 3 is the next generation release of the YUI Library.

YUI Test

YUI Test is a complete testing framework for JavaScript and Web applications. You can use the simple JavaScript syntax to write unit tests that can be run in web browsers or on the command line, as well as functional tests to be run in web browsers. Additional tools that build on top of the JavaScript library\'s core functionality allow integration with build systems.