<form action="save.php" method="POST" onsubmit="return potwierdz()">
                                    <label for="start-time">Czas włączenia: </label>
                    <input id="start-time" type="time" name="start-time" value="22:08" required>

                    <label for="end-time">Czas wyłaczenia: </label>
                    <input id="end-time" type="time" name="end-time" value="22:22" required>


                    <input type="hidden" id="pin" name="pin" value="16">
                    <button type="submit">Zapisz</button>
</form>