<?php
ob_start();
$host="localhost"; // Host name
$username="root"; // Mysql username
$password="exik"; // Mysql password
$db_name="realmd"; // Database name
$tbl_name="account"; // Table name

// Connect to server and select databse.
mysql_connect("$host", "$username", "$password")or die("cannot connect");
mysql_select_db("$db_name")or die("cannot select DB");

// Define $myusername and $mypassword
$myusername=$_POST['myusername'];
$mypassword=$_POST['mypassword'];

// To protect MySQL injection (more detail about MySQL injection)
$pass = sha1(strtoupper($myusername).":".strtoupper($mypassword));

$sql="SELECT * FROM $tbl_name WHERE username='$myusername' and sha_pass_hash='$pass'";
$result=mysql_query($sql);
$row = mysql_fetch_array($result);
$row['gmlevel'] = $_SESSION['gmlevel'];

// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $myusername and $mypassword, table row must be 1 row

if($count==1){
// Register $myusername, $mypassword and redirect to file "login_success.php"
session_register("myusername");
session_register("mypassword");
header("location:login_success.php");
}
else {
echo "Wrong Username or Password <a href='main_login.php'>Zpet</a>";
}

ob_end_flush();
?>