[html-formfu] "dynamic forms"

[Andreas Marienborg]

Has anyone ever done anything with "dynamic forms", forms that change  
when the users input changes? Specificaly I was thinking about chaning  
some constraints based on the selected value in a dropdown.

The dropdown is a country dropdown, and I would like to change some  
constraints for mobilephone, address, zipcode etc

Just wondering how I should implement such a scheme. I could perhaps  
use when-clauses but it would quickly become cluttered

- andreas