Doing what you ask will land you in the Jakob Nielsen Hall of Shame: having the UI change as it is being used can be disconcerting to a user ... think of Microsoft's "adaptive menus".

Anyhow, you can change (for example) the contents of an HTML select when the value of some other field changes by having an onChange for an field that rewrites the content of the SELECT.options array for an HTML select tag.

Notice this is client-side Javascript. No need to do anything on the server-side except send the Javascript with the served HTML.