function validate_form(thisform) {
    var invalid = "invalid!";
    var not_selected = "not selected!";

    with (thisform) {
        if (validate_required(firstname, "Firstname " + invalid) == false) {
            firstname.focus();
            return false;
        }
        if (validate_required(lastname,"Lastname "+invalid)==false) {
            lastname.focus();
            return false;
        }
        if (validate_required(email,"E-mail address "+invalid)==false) {
            email.focus();
            return false;
        }
        // phone [optional]
        // country [optional]
        if (validate_required(subject,"Subject "+invalid)==false) {
            subject.focus();
            return false;
        }
        if (validate_required(message, "Message body " + invalid) == false) {
            message.focus();
            return false;
        }
    }
}