Mozilla wants to remove XUL markup language support from Firefox

Mozilla is considering parting with its XML User Interface Language. With the development of the web, markup language would have become obsolete. Mozilla is still unsure how to say goodbye to the language.

Mozilla built the XML User Interface Language, or XUL for short, for its Firefox browser and Thunderbird mail client, among other things. The standard describes various elements, such as windows, widgets and scripts. XUL makes it easier and faster for developers to build an interface.

XUL was once developed to fill the ‘gaps’ left by HTML in web applications. That writes Dave Camp, Mozilla’s Director of Engineering. However, according to him, web technology has improved to such an extent that Mozilla’s markup language has become obsolete. The same would apply to XBL, for formatting XML documents.

“Because XUL and XBL are not web technologies, they don’t get the same attention that HTML does. Performance issues aren’t solved, which leads to a lot of unnecessary complexity in the Gecko layout engine,” said Camp. “It’s further off the web — and that doesn’t help anyone.”

Camp is committed to getting Mozilla to remove XUL and XBL support from Firefox. He does not yet know exactly how and when this should happen. “The discussion on that is still in its early stages. There are still many unanswered questions, such as what technologies should we use to replace them.”

In an email he calls on developers to think about the ‘foundations’ of the future Firefox. Camp believes this will take some time. That is not surprising: removing the XUL and XBL support can have major consequences for the makers of extensions, among others.