อยากทำแบบนี้อะครับ แต่ผมไม่เห็นภาพช่วย ยกตัวอย่างให้ดูหน่อย

<? session_start()?>
<form>
<input type="text" name="txtuser">
<input type="password" name="txtpass">
<input type="text" name="OK" value="login">
</form>

<?
if($OK == "login")
{
  $sql = "SELECT* FROM TB_user WHERE username = '$txtuser' AND password = '$txtpass'";
  $res = mysql_query($sql) or die (mysql_error());
  $row = mysql_fetch_array($res);
  $chkrow = mysql_num_rows($res);

  if($chkrow > 0)
  {

    //set session
    $_SESSION["username"] = $row["username"];
    $_SESSION["password"] = $row["password"];

    //set cookies
    setcookie("username",$_SESSION["username"],time()+30000000);
    setcookie("password",$_SESSION["password"],time()+30000000);

  }
  else
  {
    echo "ไม่มีรหัสนี้ในระบบ";
  }
}
?>

setcookie("username",$_SESSION["username"],time()-30000000);
setcookie("password",$_SESSION["password"],time()-30000000);
session_destroy();