<?php
     $servername = "localhost";
     $username = "root";
     $database= "baza4tibgr2";

     $db = mysqli_connect($servername,$username);
     $db_selected = mysqli_select_db($db,$database);
?>
<?php
   include("config.php");
   session_start();

   if($_SERVER["REQUEST_METHOD"] == "POST") {

      $username = $_POST['login']);
      $password = $_POST['password']);


      $sql = "SELECT id_user FROM users WHERE
      login = '$username' and haslo = '$password'";

      $result = mysqli_query($db,$sql);

      $row = mysqli_fetch_array($result);
      $count = mysqli_num_rows($result);

      if($count == 1) {
         $_SESSION['login_user'] = $username;

         header("location: xd.php");
      }else {
         $error = "xd";
      }
   }
?>