Thanks but nothing gets displayed, blank page.
- What's a blank page? get_count.php? I can't help you with that one because I don't have access to your database - so I'd have no idea what you're doing wrong.
If your comments id is inserted via PHP on load, then do so, I don't see the problem:
var my_xmlhttputil = new XML_HTTP_Util();
var handleCount = function(response)
document.getElementById("count").innerHTML = "Comment added ("+response.responseText+")";
my_xmlhttputil.sendRequest("get_count.php?id=<?php echo($_GET['id']) ?>",true,handleCount);