YUI Library

YUI Library

The YUI Library is a set of utilities and controls, written with JavaScript and CSS, for building richly interactive web applications using techniques such as DOM scripting, DHTML and AJAX. YUI is available under a BSD license and is free for all uses.
Development on YUI began in 2005 and Yahoo! properties such as My Yahoo! and the Yahoo! front page began using YUI in the summer of that year. In February 2006 YUI was released for public use under BSD. It is actively developed by a core team of Yahoo! engineers.
YUI is proven, scalable, fast, and robust. Built by frontend engineers at Yahoo! and contributors from around the world, it's an industrial-strength JavaScript library for professionals who love JavaScript.

There are currently two versions of YUI: YUI2 and YUI3. Both are proven, scalable, fast, and robust. The version of YUI that is best for you depends entirely on your needs and project requirements. The following provides some guidance on choosing between the versions of YUI.

YUI 2 — ROBUST AND PROVEN

YUI 2 is a JavaScript and CSS library with more than 30 unique components including low-level DOM utiltiies and high-level user-interface widgets. Currently at version 2.8.0r4, YUI 2 is robust, proven, time-tested, and extensively documented.

  • Launched February 2006
  • Used on thousands of sites around the Web — including Yahoo!
  • One of the most popular, best-documented JavaScript/CSS libraries available
  • Comprehensive suite of utilities and widgets

YUI 3 — YUI EVOLVED

YUI 3 is Yahoo!'s next-generation JavaScript and CSS library; it powers the new Yahoo! homepage and incorporates what we've learned in five years of dedicated library development.

  • Launched September 2009
  • YUI's next-generation framework — used on the new Yahoo! home page
  • Rebuilt from the ground up to be incredibly fast, powerful, and secure
  • Full suite of utilities; widgets coming in 2010

YUI is one of several high-quality JavaScript/CSS libraries. This is a good thing — it means that developers are now choosing from several good options, whereas five years ago we were solving most library-style problems on our own. Given the other choices out there, why would you choose YUI?