if($reg_username=="" or $reg_pass=="")
{
echo "<h2>Error : ¡ÃسҡÃÍ¡¢éÍÁÙÅãËé¤Ãº!!</h2>"; exit();
}
include ("../connect_db.php");
$sql="SELECT * FROM user AS a INNER JOIN user_type AS b ON (b.user_type_id=a.user_type_id) WHERE reg_username='$reg_username' and reg_pass='$reg_pass' ";
//$sql="select * from carbinet where car_id='$car_id' ";
include ("../connect_db.php");
mysql_select_db($dbname); เพิ่มตัวนี้
$sql="SELECT * FROM user AS a INNER JOIN user_type AS b ON (b.user_type_id=a.user_type_id) WHERE reg_username='$reg_username' and reg_pass='$reg_pass' ";