XUL

XUL (XML User Interface Language) is Mozilla's XML-based language that lets you build feature-rich cross platform applications that can run connected or disconnected from the Internet. These applications are easily customized with alternative text, graphics and layout so they can be readily branded or localized for various markets. Web developers already familiar with Dynamic HTML (DHTML) will learn XUL quickly and can start building applications right away. Check out the XUL Periodic Table in Firefox or another Gecko-based browser to see some XUL demos.

XUL relies on multiple existing web standards and web technologies, including CSS, JavaScript, and DOM. Such reliance makes XUL relatively easy to learn for people with a background in web-programming and design.

XUL has no formal specification and does not inter-operate with non-Gecko implementations. However, it uses an open source implementation of Gecko, tri-licensed under the GPL, LGPL, and MPL.

Mozilla provides experimental XULRunner builds to let developers build their applications on top of the Mozilla application framework and of XUL in particular.

XUL provides a portable definition for common widgets, allowing them to move easily to any platform on which Mozilla applications run.

Programmers typically define a XUL interface as three discrete sets of components:


 * 1) content: the XUL document(s), whose elements define the layout of the user interface.
 * 2) skin: the CSS and image files, which define the appearance of an application.
 * 3) locale: the files containing user-visible strings for easy software localization.