Untitled

<?php
    if (ISSET($_POST['submit'])) {
        // do what you want to do
        exit(header('location: ' . $_SERVER['PHP_SELF']));
        // header() can only be used before any html ouput including white space(s)
    }
?>
<!DOCTYPE html>
<html>
<body>
    <form action="" method="POST">
        <!-- your inputs here -->
    </form>
</body>
</html>