[dj_john]

i am new at ajax and comet, and I'm trying to create messaging system here is the main page , and i have the user's id from the class (.h99) I'm passing it as (lon) to read.php then getting the file name from the database .
everything is working fine ,but when i click on the user link nothing happening and the message box not refreshing to the new file name ,but it does after clicking and writing something, i need help to solve this problem .
$(document).ready(function(){
$('.friendclick').click(function(){
dat2=$(this).data('frclick');
$('.h99').val(dat2);
comet(dat2);
});
});
var timestamp = null; //read
function comet(dat2) {
$.ajax({
type : 'Get',
url : 'includes/read.php?timestamp=' + timestamp,
async : true,
cache : false,
data: "lon="+dat2,
success : function(data) {
var json = eval('(' + data + ')');
if(json['msg'] == ''){
$('#msg').html('No msg');
}else {
$('#msg').html(json['msg']);
$('#msg').animate({scrollTop: $('#msg').get(0).scrollHeight},200);
}
timestamp = json['timestamp'];
setTimeout('comet(dat2)', 1000);
},
error : function(XMLHttpRequest, textstatus, error) {
alert(error);
setTimeout('comet(dat2)', 15000);
}
});
}and here is the read.php , i get the ($file_name) from the DB$filename = 'messaging/'.$file_name.'.txt';
$last = isset($_GET['timestamp']) ? $_GET['timestamp'] : 0;
$current = filemtime($filename);
while( $current <= $last) {
usleep(100000);
clearstatcache();
$current = filemtime($filename);
}
$response = array();
$response['msg'] = file_get_contents($filename);
$response['timestamp'] = $current;
echo json_encode($response);