contoh-code-tidak-rapi.php

<?php
session_start();
require 'config.php';
if(isset($_POST['username']) && isset($_POST['password'])) 
{

$sql_check = "SELECT nama, 
level_user, 
id_user 
FROM users 
WHERE 
username=? 
AND 
password=? 
LIMIT 1";

$check_log = $dbconnect->prepare($sql_check);
$check_log->bind_param('ss', $username, $password);

$username = $_POST['username'];
$password = md5($_POST['password']);

$check_log->execute();

$check_log->store_result();

if ($check_log->num_rows == 1)
{
$check_log->bind_result($nama, $level_user, $id_user);

while ($check_log->fetch())
{
$_SESSION['user_login'] = $level_user;
$_SESSION['sess_id']    = $id_user;
$_SESSION['nama']       = $nama;
}

$check_log->close();

header('location:on-'.$level_user);
exit();

}
else
{
header('location: login.php?error='.base64_encode('Username dan Password Invalid!!!'));
exit();
}


} else {
header('location:login.php');
exit();
}