At my last job, when I first started there (this was circa around 2006), we actually used a Firefox browser plugin with a custom XUL interface to enable our writers to write content faster. It has a very complex UI, as complex as anything that could be found in the browser itself. Thousands of lines of XML and JS.
XUL was deeply unpleasant to use and maintain, and I do not miss it at all. We eventually ended up rewriting it as a standard webapp. It made the writers a bit slower, but they adapted eventually.
It's used for things like pop-up menus, (i.e. things that can't be done with HTML) and was recently used in some obscure parts of the UI e.g. certificate viewer (however I'm not even sure that's still XUL any more)
I think it's safer to say: It's almost all HTML these days. XUL is very much deprecated.
It’s a mixture of XUL and HTML nowadays. The reason is, most of the things that were only available in XUL are now possible in HTML, and it’s eaaier to find developers who know HTML.
I agree, but also it’s the fact that there’s a steady supply of devs who already know decent HTML, while not many who know XUL. It would be easy to apply your HTML knowledge to XUL, but since we already support interleaving HTML and XUL, why not let people just use what they’re used to?
That said, I didn’t really look into it all that much! I just happen to know about it because I was doing some userChrome.css stuff back in the day.
