Untitled

<?php

include("required.php");
session_start();

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

      $myusername = mysqli_real_escape_string($db,$_POST['login']);
      $mypassword = mysqli_real_escape_string($db,$_POST['password']);

      $sql = "SELECT * FROM usuarios WHERE login = '$myusername' and password = '$mypassword'";
      $result = mysqli_query($db,$sql);
      $row = mysqli_fetch_array($result,MYSQLI_ASSOC);
      $active = $row['active'];

      $count = mysqli_num_rows($result);


      if($count == 1) {
         session_register("myusername");
         $_SESSION['login_user'] = $myusername;

         header("location: calendario.php");
      }else {
         $error = "Your Login Name or Password is invalid";
      }
   }
?>
<html>
<head>
<link rel="stylesheet" type="text/css" href="css/login.css">
</head>

<div class="login-page">
  <div class="form">
    <form class="login-form">
      <input type="login" name="login" placeholder="Usuario"/>
      <input type="password" name="password" placeholder="Contraseña"/>
      <button>Login</button>
    </form>
  </div>
</div>
</html>

<?php
   define('DB_SERVER', 'localhost');
   define('DB_USERNAME', 'root');
   define('DB_PASSWORD', '');
   define('DB_DATABASE', 'calendario');
   $db = mysqli_connect(DB_SERVER,DB_USERNAME,DB_PASSWORD,DB_DATABASE);
?>