<?php session_start();
require_once('config.php');

// Retrieve username and password from database according to user's input
$input_username = mysql_real_escape_string($_POST['username']);
$login = mysql_query("SELECT * FROM user WHERE username = '".$input_username."'" );

$sql = "UPDATE user SET logindate = NOW() WHERE username = '" . mysql_real_escape_string($_SESSION['username']) . "'";

// Check username and password match
$row = mysql_fetch_array($login);
if (mysql_num_rows($login)) {
        if($row['password'] === md5($_POST['password'])){
             $_SESSION['username'] = $_POST['username']; // store in session
        echo header('Location: loginerror.php');
              exit;
}
?>