<h1>Form</h1>
<form id="form" action="/" method="post">
    <div>
        <label for="name">Adınız:</label>
        <input type="text" id="name" name="name" />
    </div>
    <div>
        <label for="email">E-posta:</label>
        <input type="email" id="email" name="email" />
    </div>
    <div>
        <input type="submit" value="Gönder" onclick="post()" />
    </div>
</form>
<div>
    <p>Kalan süre: <span id="countdown"></span> saniye</p>
</div>
<script>
    function post() {
        var form = document.getElementById("form");
        var countdown = 10;
        var timer = setInterval(function () {
            countdown--;
            if (countdown <= 0) {
                clearInterval(timer);
                form.submit();
                return;
            }
            document.getElementById("sayac").textContent = countdown;
        }, 1000);
        document.getElementById("sayac").textContent = countdown;
        document.querySelector('#form input[type="submit"]').disabled = true;
    }
</script>