Fetch new MySQL entries and append to existing div's dynamically - php

Question

I have a PHP script to selected records for comments from a database, and then print them onto the page. What I'd like to happen is that if a user is on a page, and another user comments on an item on said page, it automatically appends the new comment to the bottom. The problem I'm having is that I don't know how to differentiate between all of the statuses.
My code for generating the comments on a status is:
<?php
$rt = ("SELECT * FROM (SELECT comment as comment, byuid as byuid, comuid as comuid, likes as likes, dislikes as dislikes, UNIX_TIMESTAMP(timestamp) as timestamp FROM mingle_comments WHERE onuid = '$sid' AND type = 'status' ORDER BY timestamp DESC LIMIT 2) mingle_comments ORDER BY timestamp ASC"); //query
$result = mysql_query($rt) or die (mysql_error());
if(mysql_num_rows($result) >= 2) {
?>
<div id="sa" style="background:#E0E0E0; padding:5px 5px 5px 5px;">
View all comments...
</div>
<?php
}
while($st = mysql_fetch_assoc($result)) {
$comment = nl2br($st['comment']);
$by = $st['byuid'];
$comuid = $st['comuid'];
$time = $st['timestamp'];
$l = $st['likes'];
$d = $st['dislikes'];
$bq = "SELECT * FROM users WHERE uid = '$by' LIMIT 1";
$bqq = mysql_query($bq) or die (mysql_error());
while($bqr = mysql_fetch_assoc($bqq)) {
$dp = $bqr['dp'];
$fbq = $bqr['fname'];
$sbq = $bqr['sname'];
}
?>
<div id="commentbox" class="<?php echo $comuid; ?>" style="padding:5px 5px 5px 5px;">
<div id="cbi" style=" display:inline; position:relative; ">
<img src="<?php if ($dp == null) { echo 'img/unknown_user.jpg'; } else { echo "pf/" . $by . "/" . $dp; } ?>" width="36px" style=" display:inline; position:relative;"/>
</div>
<div id="cbt" style="position:relative; margin-left:32px; margin-top:-35px;">
<?php echo $fbq . " " . $sbq; ?>
<p class="<?php echo $comuid; ?>" style="position:relative; margin-left:5px;"><?php echo $comment; ?></p>
</div>
<div id="clb" style="background:#E0E0E0; padding-left:5px;">
Like<?php echo time_since($time); ?>
</div>
</div>
<?php
}
?>
TL:DR; How can I automatically fetch new comments and append them to the comments generated in the above script without page refresh.

Answer 1

JQUERY
$(document).ready(function(){
var lastcheck='';
setInterval(function() {
$.ajax({
url: 'URL_TO_PHP_SCRIPT',
type: 'POST',
data: {'lastcheck':lastcheck},
success: function(result){
if (result!='nothing_new'){
lastcheck=result.lastcheck /*Update lastcheck*/
var data=result.data;
$.each(data, function(i,val){
//Foreach comment you do what you need, like append, prepend, etc. data[i]."key" to get the value.
});
}
}
});
}, 15000 /* This will check each 15 seconds, you can change it */);
});
PHP SIDE
$lastcheck=$_POST['lastcheck'];
/*
You should add a date field to each new created comment,then filter by "orderby date > $lastcheck" so you get comments since your last check
You get the new comments here
...
...
..
*/
if (!empty($arrayofnewcomments)){
/*The output*/
echo json_encode(array('lastcheck'=>date('Y-m-d H:i:s'),'data'=>$arrayofnewcomments));
}else{/*No new comments*/
echo 'nothing_new';
}
This is some code I came up with, it's a general Idea but it works. It will check each 15 seconds for new comments.