$error = $login = $parol = "";

if (isset($_POST['login']))

{

$login = $_POST['login'];

$parol = $_POST['parol'];

if ($login == "" || $parol == "")

{

$error = "Not all fields were entered<br />";

}

else

{

$query = $con-> query("SELECT login,parol FROM users

WHERE login='$login' AND parol='$parol'");

if($query->num_rows > 0){

$error = "<span class='error'>Username/Password

invalid</span><br /><br />";

}

else

{

$_SESSION['login'] = $login;

$_SESSION['parol'] = $parol;

header('location: index.php');

}

}

}

<div class="title">Kirish</div>

<div class="menu">

<form action="login.php" method="POST">

Login:<br> <input type="text" name="login"/><br/>

Parol:<br> <input type="password" name="parol"/><br/>

<input type="submit" value="Kirish" class="button"/>

</form>

</div>

<div class="forlink"><a href="/reg" class="links"><img src="/img/reg.png" alt="reg">Registratsiya</a></div>

    <div class="forlink"><a href="/forgot" class="links"><img src="/img/help.png" alt="help">Parolni unutdim?</a></div>