YUI recommends YUI3.

YUI 2 has been deprecated since 2011. This site acts as an archive for files and documentation.

This documentation is no longer maintained.

YUI 2 — Yahoo! User Interface Library

YUI 2 — Yahoo! User Interface Library

YUI 2 is a JavaScript and CSS library with more than 30 unique components including low-level DOM utilities and high-level user-interface widgets. Currently at version 2.9.0, YUI 2 is robust, proven, time-tested, and extensively documented.

Note: All YUI 2.x users should review the YUI 2.8.2 security bulletin, which discusses a vulnerability present in YUI 2.4.0-2.8.1. If you host an a YUI 2.4.0-2.8.1 distribution, you need to take action — review the bulletin for full details.

Getting Started

  1. Check out the examples of YUI in action. We recommend starting with the Event Utility and Dom Collection examples; Event and Dom are part of the YUI Core (along with the YAHOO Global Object) and provide an important foundation for JavaScript developers using YUI. Once you've reviewed those foundational pieces, go on to explore utilities like Drag and Drop and Animation or UI controls like Button, Calendar and TabView. If you're interested in YUI's CSS components, read through the examples for Reset, Base, Fonts, and Grids in that order.
  2. Remember that there are full user's guides for each component here on the website. If you have any questions about a component as you play with the examples, check out the component's user's guide (by following any of the links along the left side of the page) or the searchable API documentation.
  3. YUI 2.8: Learning the Library from Packt provides an excellent introduction to YUI 2. Written by one of the most active members of the YUI community, it is an excellent reference for newcomers and experts alike.
  4. Articles: Check out "Writing Your First YUI Application," an article designed to help you get up and running with YUI, and "Loading YUI: Seeds, Core, and Combo-handling," an article that explores the three most common strategies for including YUI on the page.
  5. Start building. You can include YUI scripts and CSS from the YUI download (in the download's /build directory) or directly from Yahoo! servers. The YUI Loader Utility is a client-side loading package that can dynamically pull in YUI scripts as needed, whether from your servers or from ours. And the YUI Dependency Configurator is a great way to calculate an optimized list of script/css includes for your particular implementation.
  6. Become a member of the YUI community. YUI developers and implementers share thoughts and solutions and provide a helping hand in our forums. YUI developers also contribute to the YUIBlog, where you'll find in-depth articles, videos and other great content about YUI and the world of frontend engineering.


All of the YUI Library components are provided free of charge under a liberal BSD license.

Support & Community

The YUI Library and related topics are discussed on the on the YUILibrary.com forums.

Also be sure to check out YUIBlog for updates and articles about the YUI Library written by the library's developers.

Filing Bugs & Feature Requests

The YUI Library's public bug tracking and feature request repositories are located on the YUILibrary.com site. Before filing new feature requests or bug reports, please review our reporting guidelines.

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