What technology does Facebook use to auto-update information on a page without reloading it?
For example, while someone is viewing his profile if he receives a new message the inbox number auto-updates in the top bar. Same with wall posts, etc. Code-wise how is this managed?
They are using several new technologies like AJAX and History API. I strongly recommend you to use jQuery or another framework for AJAX and History.js for the History API.
the core javascript function set_timeout() is the man! Every x seconds the server is queried to fetch new results, updates etc. FB uses AJAX to get the info from the server and JS to update the page.
Facebook open a connection using AJAX which then hangs and hangs. The server doesn't send anything or respond to your browser unless, of course, a notification. Eventually, your browser may give up and disconnect from Facebook in which case the javascript will create a new connection and the process continues.
This is superior to polling the server every few seconds as it reduces load and makes load more predictable too.
Here's more info: http://en.wikipedia.org/wiki/Comet_%28programming%29
use setInterval on a function which makes an Ajax call to a file in which you have a MySQL query which checks something.
setInterval( "refresh();", 60000 );
refresh = function(){
var URL = "file.php";
$.ajax({ type: "GET",
url: URL,
succes: function(data){
if(data){
//change stuff
}
}
});
}
that should be a good starting point
coba gunakan script ini..
<html>
<head>
<script type="text/javascript" src="jquery.min.js"></script>
<script>
$(document).ready(function(){
var callAjax = function(){
$.ajax({
method:'get',
url:'load.php',
success:function(data){
$("#sample").html(data);
}
});
}
setInterval(callAjax,5000);
});
</script>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body>
<?php
<div id='sample'>100 </div>";
?>
</body>
</html
<?php
mysql_connect("localhost","root","siantarman");
mysql_select_db("konsultasi") or die("<br><br><hr width=350 size=1 align=left>
<font color=red><b>Database belum tersambung!</font></b>
<br>Hubungi administrator anda!<br>" . mysql_error());
$sql_info=mysql_query("select jumlah from data_konsultasi where id = '9'");
$r_data=mysql_fetch_array($sql_info);
echo"$r_data[jumlah]";
?>
selamat mencoba..