Form Submission Counter Example

<?php
$f = fopen('counter.txt', 'r+');
flock($f, LOCK_EX);
$total = (int) fread($f, max(1, filesize('counter.txt')));
if (isset($_POST['submit'])) {
rewind($f);
fwrite($f, ++$total);
}
fclose($f);
?>


<form action='' method="post">
<input type="submit" name="submit" value="click" />
</form>
This button has been clicked <?php echo $total; if($total >= 100){echo 'More then 100';} ?> times.