การแสดงรายชื่อสมาชิกที่กำลังออนไลน์อยู่ในระบบ ยกเลิกการแสดงเมื่อปิดบราวเซอร์

<?
session_start();
$user = $_GET["user"];
$pass = stripslashes($_GET["pass"]);


include("../common.php");
$con = mysql_connect( $mysql_host,$mysql_user,$mysql_pass );
mysql_select_db($mysql_db) or die ("not connect database");
mysql_query("SET NAMES UTF8");
	$sql = "select * from table_register where code = '$user'";
	$qry = mysql_query($sql);
	$nrows = mysql_num_rows($qry);
	if($nrows != 0){
		$rsl = mysql_fetch_array($qry);
		$code_pass = $rsl["pass"];
		if($pass == $code_pass){
			$_SESSION["login_status"] = "ok";
			$_SESSION["code"] = $rsl["code"];
			$_SESSION["nickname"] = $rsl["nickname"];
			$_SESSION["prive"] = $rsl["prive"];
			
			$sql = "update table_register set online = '1' where code = '$user'";
			mysql_query($sql);
		
			echo "OK";
		
		}else{
			echo "รหัสผ่านไม่ถูกต้อง";
		}
	  }
		else{
			echo "รหัสนักศึกษานี้ไม่มีในระบบ";
	}  


mysql_close($con);
?>

<?
session_start();

$code = $_GET["code"];
include("common.php");
$con = mysql_connect( $mysql_host,$mysql_user,$mysql_pass );
mysql_select_db($mysql_db);

$sql = "update table_register set online = '0' where code = '$code'";
mysql_query($sql);

mysql_close($con);

session_unset();
session_destroy();
header("Location:index.php");
?>