XUL stands for XML-based User-interface Language. It is an application of XML used to describe window layout in the Mozilla browser. It is pronounced zool (to rhyme with "cool").
Other applications, such as the Mozilla Amazon Browser (MAB) and ChatZilla, have been created that, while not stand-alone, are XUL-based and do not use the browser part of Mozilla. The interesting thing about these applications is that many can simply be opened from the Internet directly, just like a website. This is called a remote application.
An XUL user interface is typically defined as three discrete sets of components:
- XUL content: This typically declares windows and user interface elements associated with them.
- XUL skin: Contains style sheets and images to define the appearance of an application.
- XUL locale: Displayable text within an application is partitioned and stored within locale specific files for easy language portability.
