[jQuery] [Validate]e-mail validation

[ymai]

Hello everyone
I notice that an e-mail address like
ad...@foo_bar.net
seems to be valid for jQuery Validate (http://bassistance.de/jquery-
plugins/jquery-plugin-validation/) but invalid for the PHP
"filter_var" function
(http://www.w3schools.com/PHP/func_filter_var.asp)
The underscore caracter is valid in the username but is it valid in
the domain name?
I'm afraid jQuery is wrong here.