Xul

Looks like I am headed to CHI 2007 to participate in a session on user interface description languages. The session will explore the use of markup language UI’s (such as XUL, XAML and Flex) in prototyping user interfaces before handing them off for system integration. This could allow the interaction designer/engineer to become a more integral part of the iterations in the development cycle.

In December, Robert O’Callahan had a post about the large amount of XUL-based development happening without much visibility. Mozilla wants to find out as much as possible about such development. At Solutions Linux 2007, there was a Mozilla/XUL Round Table session to examine the potential of the Mozilla platform through success stories. From what I have seen (mostly in French) it was quite a successful session. Some of the demos and stories included:

I put together a simple XUL validator based on the ideas in my last post. There is a primitive front end where you can put XUL into a textarea and validate it. The validator is completely client-side JavaScript with a simple JSON rules file. You can view the source and the rules from the validator “Tests” page.

A validator for XUL could be a good idea. I am thinking about something more than just ‘schema’ validation. Something to help with best practices and accessibility. Maybe ‘validator’ isn’t the right word. Here are some checks that could be useful:

A few common questions seem to be asked a lot, especially by developers new to the Mozilla platform. So, I wanted to draw attention to some relevant articles on the Mozilla Developers Center (MDC).

I was a little surprised how “popular” my XUL/E post became. The demo viewer page alone has over double the hits of the second place page. In that post, I demonstrated how Mozilla’s rendering engine (Gecko) could be embedded in Internet Explorer and used to display rich XUL applications and advanced SVG and canvas graphics. Of course, XUL/E is a play on Microsoft’s brand-new-fantastic-sliced-bread WPF/E technology and Mozilla is not mounting a XUL/E initiative (but I can dare to dream).

Cédric Savarese has a demo of using XUL to make a richer HTML form. Cédric’s approach is different than my XUL-in-Internet Explorer idea. His method only uses XUL in a XUL-enabled browser (Firefox, SeaMonkey or Netscape). In other browsers, it falls back to DHTML elements.