XUL is an XML-based technology for expressing the GUI part of a software application. It has been used to express GUIs for applications as diverse as web browsers, email clients, calendars, calculators, spreadsheet editors, HTML editors, debuggers, and whole desktop environments. The free Mozilla platformthat is, the executable engine and libraries that accompany every Mozilla-based productprovides a fully-featured implementation of XUL. This article is a quick look at the main tags that Mozilla's XUL provides. Mozilla is also the name of the applications that will pick up where Netscape's products have stopped. It's a name worth getting used to.
When dealing with technical people, pronounce XUL the cool way: "zool." When dealing with humorless technophobes, pronounce the individual letters: "eks you ell." XUL is both funky and dignified.