Don't use regular expressions to "validate" email addresses

[Tim Williams]

> >
> Just as a matter of interest, are you expecting that you'll find out
> about the undeliverable ones? Because in many cases nowadays you wont,
> since so many domains are filtering out "undeliverable mail" messages as
> an anti-spam defence.
>

...and then there is the problem of validating that the valid email
address belongs to the person entering it !!      If it doesn't,  any
correspondence you send to that email address will itself be spam (in
the greater modern definition of spam).

You could allow your form to accept any email address,  then send a
verification in an email  to the address given,  asking the recipient
to click a link if they did in fact fill in the form.  When they click
the link the details from the original form are then verified and can
be activated and processed.

HTH :)