Rails - May 2005 - Changing an Options Select Box's contents

I have a form whose parameters are used to create a new request object.  
The request object has a person field that tells it who submitted the 
request.  There are 3 levels of information that are used to choose the 
person: state, city, and finally the persons name.  This is to prevent 
the user from having to sift through all the possible choices for a 
person as there will be several thousand in the system.   I want to have 
the state selection leave only valid cities in the city option select 
box and the city choice leave only people who live in that city in the 
person option select box.  I assume that using javascript this can be 
done rather simply?  Does rails provide any shortcuts and how would I 
code something like this?  In short, how would I go about changing the 
contents of an options select box in a form based on previous inputs to 
other fields in the form?



Thank you,
Matthew Margolis