Form Change Based Upon Criteria Selected?

Is it possible (and if so, how?) to have an asp form page that based upon a user's selection on a field, would generate a input field b that the user selects?

For example:

User selects "name" in a select statement which would list the possible names to select from or if the user selects "telephone" in the same select statement then it would list the possible telephone numbers to select from.

Or simpler:

If user selects A then show P to select from or
if user selects B then show Z to select from.