Mozilla, the developers behind the Firefox web browser, recently made an announcement that they will no longer be using XUL (XML User Interface Language) to render its graphical user interface. Instead, it will be switching to more commonly used web technologies such as HTML elements and CSS.
XUL was a GUI language dating back to Mozilla’s history when it started with Netscape in 1997. It found a future in Firefox with the release of the browser and the new name a year later. Initially, there was openness from third-party developers to use the language for their UI.
However, with HTML5, interest in XUL had waned. In his announcement that the XUL layout is now a thing of the past, Mozilla developer Emilio Cobos Álvarez unadornedly named the language’s weaknesses, including that it never supported some popular CSS features, the software was poorly documented and had no active maintainer.
Álvarez also showed in his blog what difficulties the Mozilla team had to contend with and how they managed a smooth transition between the XUL and web technology. Due to the extensive code, the transition could not be managed in one big step. Instead, an incremental approach was offered, in which the programmers could test and understand the effects of their changes using an XUL emulation. It took the developers nine years to make the switch.
Mozilla will still need to use XUL for OS native panels and menus, but the language has been deprecated in its latest release. The consistent use of weaving technology also promises an increase in speed and fewer bugs.
This change by Mozilla shows that even established technologies must be updated and change to meet the evolving needs of users. It remains to be seen how other web browsers will respond to Mozilla’s switch to a more web development-friendly UI.
