[Zope] Client Side Form Field Validation - How to ?

[Luca Manini]

Hi,=20

the subject says it (almost) all.

Taken for granted that one should validate input "also" on the server,
everybody (even me) knows many reasons (no post, faster and more
user-friendly messsages, ...) for doing something on the client.=20

The first thing that comes to (my) mind is Java (o JavaScript ?).
Or would be possible to write some Python (Jython) ?
Anyhting already available ?
Anything "declarative" (like usign regexp) ?

	TIA, Luca