X is a collection of loosely-bound, cross-browser, Javascript functions and objects. It is intended to be a resource from which you pick and choose - you do not have to include the entire library in your application. It contains core DOM/Style functions, unobtrusive enhancements, utility functions, objects such as menus and tab panels, and also has some experimental stuff. I've been developing this library since 2001 (I started its predecessor in 1999). Thanks to thousands of people like yourself X has been extensively tested on a wide range of operating systems and browsers. Thanks to your contributions X continues to improve and evolve.