I've tried that link, but the javascript code didn't work for me - I get a scrambled dropdown box in CourseName.

My general solution is to get the code to work *without* javascript first (i.e. use request/response type reloading), and when you've done that, try to improve on it with AJAX technologies - and if you can't get it to work on a specific browser, fall back to the level you *know* that works.

I'm biased because a) I've been using linux since 1999 or something, so the most "popular" browser isn't available to me. b) I've designed a few websites for government agencies that required the web accessibility guidelines (priority one).

By the way, XMLHttpRequest code isn't all that difficult if you know how to do javascript. I believe this article from apple is good introduction. You'll be able to write your own code (with a little experimentation).

Also, you could take a look at HTML-Prototype: it's a browser-agnostic, reasonably well documented library for perl, that should take care of most of your problems.