регистрация на кирилица за firstname и lastname

[mumiqtabg]

имам част от код за регистрация въпроса ми е как да добавя и кирилица на firstname и lastname? код:

if(!ValidUserName($username)) {
throw new Exception($translate->__("Please enter a valid username."));
}

if($this->checkUserName($username)) {
throw new Exception($translate->__("Sorry, it looks like")." ".$username." ".$translate->__("belongs to an existing account."));
}

if(!ValidEmail($email)) {
throw new Exception($translate->__("Please enter a valid email address."));
}

if($this->checkUserEmail($email)) {
throw new Exception($translate->__("Sorry, it looks like")." ".$email." ".$translate->__("belongs to an existing account."));
}

if($email != $confirm) {
throw new Exception($translate->__("Your emails do not match. Please try again."));
}

if(strlen($password) < 6) {
throw new Exception($translate->__("Your password must be at least 6 characters long. Please try another."));
}

if(!ValidString($firstname)) {
throw new Exception($translate->__("The first name contains invalid characters."));
}

if(!ValidString($lastname)) {
throw new Exception($translate->__("The last name contains invalid characters."));
}

if($month == "none" || $day == "none" || $year == "none") {
throw new Exception($translate->__("You must indicate your full birthday to register."));
}

if($year >= "1999" || $year < "1905" || $month > "12" || $month < "1" || $day > "31" || $day < "1" ) {
throw new Exception($translate->__("Sorry, we are not able to process your registration."));
}

if($sex == "none") {
throw new Exception($translate->__("Please select either Male or Female."));
}
$sex = ($sex == "m")? "M" : "F";
[js][/js]

 

[vasilev]

if(!ValidString($firstname)) {
throw new Exception($translate->__("The first name contains invalid characters."));
}

а какво е ValidString ?
трябва да покажеш и функцията ValidString..