Question

When a user selects the radio button that equal sales it send information to the sales department which works fine.

I need when a user selects the support department that have to enter a 5 digit serial number for the device they need support on. The serial number has to be between 3 to 5 numbers only. If the serial is not 3 to 5 numbers example:

in this box if the numbers are 123 submit, if 12324 submit, if x3423 die, if 12 die, if 123456 die. also I need for to only accept numbers.

Can I do this

if($selected == 'sales') {
    $body = "From: $name_field\n E-Mail: $email_field\n Address: $address\n City: $city\n State: $state\n PostalCode: $zip\n Department $selected\n How did you about us: $hear\n Country: $country\n  Comments: $comment";
    mail($to, $subject, $body);
    header("Location: http://url/");
}     
else if($selected == 'support') {
    if(preg_match("/^\d{3}$|^\d{5}$/", $_POST['serial']) === 0) {
        $body = "From: $name_field\n E-Mail: $email_field\n Address: $address\n City: $city\n State: $state\n PostalCode: $zip\n Department $selected\n How did you about us: $hear\n Country: $country\n Serial Number: $serial\n  Comments: $comment";
        mail($toa, $subject2, $body);
        header("Location: http://url/");
    }
    else {
        die('<script type="text/javascript"> alert("Serial Number is invalid");</script>');
    }
}
}

Answer 1

You are currently having it send the email if the regex fails to match. Your regex is wrong too. There’s a few minor things too.

Try this:

switch($selected) {
    case "sales":
        $body = "From........................";
        mail($to,$subject,$body);
        header("Location: .....");
        exit;
    case "support":
        if( preg_match("(^[0-9]{3,5}$)",$_POST['serial'])) {
            $body = "From.......................";
            mail($toa,$subject2,$body);
            header("Location: ......");
            exit;
        }
        else {
            die("Serial Number is invalid!");
        }
    default:
        die("Invalid department selection.");
}