$email = $_REQUEST["email"];
$result = filter_var($mail, FILTER_VALIDATE_EMAIL);
var_dump($result);
$mail
, а не $email
?$email_a = 'joe@example.com';
$email_b = 'bogus';
if (filter_var($email_a, FILTER_VALIDATE_EMAIL)) {
echo "E-mail адрес '$email_a' указан верно.\n";
}
if (filter_var($email_b, FILTER_VALIDATE_EMAIL)) {
echo "E-mail адрес '$email_b' указан верно.\n";
} else {
echo "E-mail адрес '$email_b' указан неверно.\n";
}