[Zope] a warning message before performing an action

[Alan]

Dears,

I have a web page with some buttons (<form action=...) to perform some
action (by calling a python script). However, some actions (like
'delete' a picture for example) I would like to warn user before
performing it. I recall from php how to pop up a window (or a drop
down in Mac OSX) with a warning message prompting a 'Yes' or 'No'
confirmation and I was wondering how would I do it with Zope, with an
example if possible.

Any help here would be very welcome.
Cheers,

Alan