$sql = "select * from chat order by id desc limit 15";
$result = mysql_query($sql) or die ("An error has occured with in the database.");
$(document).ready(function() {
// check once in five seconds
setInterval(function() {
$.get('/script.php', {do: 'new_messages'}, function(response) {
if(response == 1) {
window.location.reload();
}
});
}, 5000);
});