Aside from a touch of CSS styling, the most I would ever do to a form field is use an input mask to provide some anticipatory data validation. So that, for exa

Aside from a touch of CSS styling, the most I would ever do to a form field is use an input mask to provide some anticipatory data validation. So that, for example, you cannot put text where a phone number is expected, and to also provide expected formatting for that phone number automagically. Or that an eMail field actually contains a properly formatted eMail and that it matches what’s in the confirmation field. You know, stuff that’s simple to implement, is not yet reaching the level of business rules, yet can help avoid a round trip to the server. And that’s it. Anything more than that is getting in the user’s way.