If i get this straight, you want to track how many times a user has clicked a download link, not the amount of times a file has been downloaded. You could do this with cookies or a Text file or using HTTP POST or GET methods via javascript, probably already a Jquery script to do it already. Example:
<?php
if(!file_exists('counter.txt')){
file_put_contents('counter.txt', '0');
}
if($_GET['click'] == 'yes'){
file_put_contents('counter.txt', ((int) file_get_contents('counter.txt')) + 1);
header('Location: ' . $_SERVER['SCRIPT_NAME']);
die;
}
?>
Then use File Downloaded: <?php echo file_get_contents('counter.txt'); ?> Times!