proses login

<?php
session_start();
require_once("config.php");
$username = $_POST['username'];
$pass = $_POST['password'];
$cekuser = mysql_query("SELECT * FROM user WHERE username = '$username'");
$jumlah = mysql_num_rows($cekuser);
$hasil = mysql_fetch_array($cekuser);
$h_user=$hasil['username'];
$h_pass=$hasil['password'];
$h_lvl=$hasil['level'];
$h_blok=$hasil['blok'];

if ($h_pass==$pass)//jika hasil password sama
{
 //maka user login
 if($jumlah ==0)//jika hasil username tidak ada atau belum terdaftar
 {
 $notif="user tidak ada";//user tidak tidak ada
 }
    else if($h_blok==="n")
                    {
                    //login user sukses
                    $_SESSION['level']      = $hasil['level'];
                    $_SESSION['username']   = $hasil['username'];
            header('location:halaman.php');
                    }
    else if($h_blok==="y")
 {
 $notif="user di blokir";//user di blokir
 }

}
else {
$notif="password salah";

}//pasword salah

?>
<span style="color:red;font-size:25px;"><?php echo "$notif";?></span>