[TYPO3-english] Formhandler: How to create chained select boxes?

[gary.wong at spingroup.com]

Does anyone know how to do chained select / dropdown boxes using the 
Formhandler extension?

Something like choose a country in one select box and then the province 
select box will update itself for the selected country?

I know how to populate the drop downs with countries, provinces, etc, but don't know how to kick off a form update to change a chained select box.

I am thinking a JS onclick event event that submits the form, then use an interceptor to redraw the form. But how do I do that without getting all the validator messages? 

A multi-page solution is possible but it would not be very user friendly on simply sign up forms, especially when we're asking for country/state.

Perhaps an ajax solution would be nice too, which can lead to many other uses.

Thanks for any help,
Gary