PHP/MySQL OnClick Update MySQL

Need to update a hitcount field in a MySQL table when a user clicks on a banner ad. Have the random ad display script working but can't figure out how to update the table when they click..assuming will have to pass the ID to Ajax but no idea how to approach it? Code is below:

include 'connection.php';
$query = "select * from ads where adtype = 'small' and status = 'yes' ORDER BY RAND() LIMIT 3";
$result = mysql_query($query) or die(mysql_error());

$num_results = mysql_num_rows($result);
if ($num_results !="0")
{
for($i=0;$i<$num_results;$i++)
{
    $row = mysql_fetch_array($result);

    $client = htmlspecialchars(stripslashes($row['client']));
    $link = htmlspecialchars(stripslashes($row['link']));
    $filename = htmlspecialchars(stripslashes($row['filename']));
    $id = $row['id'];
    echo "<tr>";
    echo "<td>";
    echo '<开发者_如何学C;a href="';
    echo $link;
    echo '"><img src="thimg/';
    echo $filename;
    echo '" alt="';
    echo $client;
    echo '"></a>';
    echo "</td>";
    echo "</tr>";

}
}                 

Make the link point to a page which takes the ID of the ad as a parameter, something like click.php?id=the_id. Then that page can update the database, look up the link, and then you can use a header redirect to forward them on to the link. Make sure you don't output anything on that forwarding page though, or the redirect won't work.

This should get you what you need, without the need for javascript or ajax.