Ben Allfree :: Painless Programming

I know that AJAX isn't the same as client-side scripting. I'm lumping them together here because you can't have much of one without the other.

I've used most of the JS frameworks out there. They all share a similar strength. They make complex cross-browser scripting easy. With them, you can hook into events, set timers, perform animations and transitions, create popups, and in general make the browser window behave like a desktop app.

Every once in a while I see some useful AJAX applications. I like edit-in-place solutions if validation is handled properly. I like Lightbox for slideshows. I kind of like what Facebook did with the profile drag-and-drop layout management.

But so often, AJAX errors and validation are improperly handled ignored because, well, it's hard to do right. How do you handle unpredictable errors with AJAX? Normally a framework or web server would return a generic error to the user. After all, the point is that something unpredictable happened. Your application didn't anticipate it, so the underlying framework caught it and ended as gracefully as possible. But when that happens in AJAX, the user doesn't see it. The AJAX operation looks like it completed, but you find out later that your data did not save.

AJAX is hard to debug, hard to fail with grace, and can sometimes get a little carried away to the point that it starts smelling like RIA. Too much animation, too much solving problems differently for its own sake.

Overall, I give AJAX a cautious thumbs up.