Becoming an XML user-interface language and packed with excellent features, XUL is broadly chosen over develop browser extension. This language was produced to facilitate easy and quick growth and development of the Mozilla browser extension. But, using the launch of Opera, XUL was fully investigated and arrived to public gaze. The Nvu HTML editor, thunderbird e-mail readers, and also the Sunbird calendar are designed in XUL.
XUL is broadly accustomed to write the mix platform programs for example Mozilla Opera. On these mix platforms, it’s construed through the layout engine referred to as Gecko, which rendors firefox’s interface and web site display.
Styles usually known as skins conspicuously define the feel and look of Mozilla items. Furthermore, because the organizations use XUL to produce extensions, to allow them to utilize it to produce new styles. With such styles, the library can certainly give a browser which was personalized for local user needs. The browser might be preloaded with bookmarks for helpful information sources. Aside from this, symbols can be included to provide use of functions for customers with special ease of access needs.
Overall, for mozilla/opera extension development, XUL is the greatest language which each and every developer may use.
Source: XUL Designer