[sourcecodelanguage='php']
/* to allow the user to regiter with email ids containing + */
add_filter( ‘sanitize_user’, ‘plus_sanitize_user’, 10, 3);
function plus_sanitize_user($username, $raw_username, $strict) {
$new_username = strip_tags($raw_username);
// Kill octets
$new_username = preg_replace(‘|%([a-fA-F0-9][a-fA-F0-9])|’, ”, $new_username);
$new_username = preg_replace(‘/&.?;/’, ”, $new_username); // Kill entities
// If strict, reduce to ASCII for max portability.
if ( $strict )
$new_username = preg_replace(‘|[^a-z0-9 _.\-@+]|i’, ”, $new_username);
return $new_username;
}