Firefox 1.5 has been released. As a result XUL is cool again. Having dealt with XUL in Mozilla 1.4 through 1.7, I know it has its place on medium-sized projects. It will be interesting to see what happens with this.
A little XUL background
Disclaimer: Just like people, languages grow to become better, and continuously reinvent themselves. This writing is what I think about this language as of 2005, having enjoyed its best features and suffered through its worst issues for a while. This may become less relevant as people address the problems.
Writing software in XUL is fun. Testing and debugging them, not so much. One of the reasons scripted applications are enjoying a bit of a revival lately is their community’s embracing of test-first approach. With a strong testing culture, something that breaks at runtime is not so bad because the automated verification test should catch it. Having said that, mozilla XUL developers as a whole definitely don’t have a test-first approach.