Creating chained select boxes with Django and Mootools

I recently put up a code snippet on djangosnippets.org detailing how to do chained select boxes with Django and Mootools.

The basic idea is you have one select box that alters the contents of another select box based on what is chosen.  The idea is pretty simple, and it is pretty easy to implement also.

I've been using Mootools to do most of my javascripting lately.  I've really been impressed with that library.