function check_input(formobj)
{

        var tarkistettavat = Array("firstname", "lastname", "streetaddress", "postalcode", "city", "phonenumber", "email");
        for (var i = 0; i < tarkistettavat.length; i++) {
            var obj = formobj.elements[tarkistettavat[i]];
            if (obj && ((obj.value == null) || (obj.value == ""))) {
                var varoitus = "Following field is missing: " + tarkistettavat[i] + "";
                alert(varoitus);
                return false;
            }
		}
}