server side / client side email validator differences

Question

I'm using the native jQuery validation library to validate email addresses entered in a contact form. Since this is an Expression Engine site, I'm using its email validator as a server side backup.

When I enter [email protected], jQuery says it's valid but when submitted, the Expression Engine validator says it is not valid.

I know that validating email addresses can get very complex but which of the two results would you consider as being "correct" ?

Answer 1

It's a technically valid email address, but it cannot be delivered to. (There are no single-character TLDs)
Take your pick.