A simple image counter can be made without Ajax like on this page (see the source). The imagecounter.php file remove, on each call, the javascript file imagecounter.js with the new value and reload it to display this one...
<?php[COLOR="Blue"]
// imagecounter.php file[/COLOR]
header("Cache-Control: no-cache, must-revalidate");
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT");
header("Content-Type:text/javascript;charset=utf-8");
$cnt=file_get_contents("imagecounter.js");
$nmb=preg_replace("`[^\d]+`",'',$cnt);
$nmb++;
$fch=fopen("imagecounter.js","w+");
$ncn='var count='.$nmb.';'.chr(13).chr(10);
$ncn.='document.getElementById("counter").innerHTML=count;';
[COLOR="Blue"]// remove the js file[/COLOR]
fwrite($fch,$ncn);
[COLOR="Blue"]// return the new script[/COLOR]
echo $ncn;
?>
A single difficulty, it would be advisable to preload the sound !