Use AJAX to determine available vocabs

(This was taken from the forums http://drupal.org/node/87851.)

I have run into an interesting situation with OG that is applicable across all node types: The organic groups og vocab now lets a person see vocabularies associated with multiple groups when the appropriate groups are selected (new feature) but it requires the user to preview their post to see the appropriate vocabs.

I would like to propose that there should be a method by which a user can select a checkbox (i.e. a group) and then the post form should dynamically update either using AJAX or by autosubmitting.

This functionality could be extended to other situations such as having "internal document" node type with subform element of "travel info", "financial info" show up based upon the taxonomic term selected. Is this now possible.