Take a look what Rasmus is talking about AJAX

He follows the rule of simplicity as he described in his framework approach.

The very basic of ajax structure -

Javascript

function createRequestObject() {

var ro;

var browser = navigator.appName;

if(browser == “Microsoft Internet Explorer”){

ro = new ActiveXObject(“Microsoft.XMLHTTP”);

}else{

ro = new XMLHttpRequest();

}

return ro;

}

var http = createRequestObject();

function sndReq(action) {

http.open(‘get’, ‘rpc.php?action=’+action);

http.onreadystatechange = handleResponse;

http.send(null);

}

function handleResponse() {

if(http.readyState == 4){

var response = http.responseText;

var update = new Array();

if(response.indexOf(‘|’ != -1)) {

update = response.split(‘|’);

document.getElementById(update[0]).innerHTML = update[1];

}

}

}

HTML

<a href=”javascript:sndReq(‘foo’)”>[foo]</a>

<div id=”foo” />

server side script(rpc.php) -

switch($_REQUEST['action']) {

case ‘foo’:

/* do something */

echo “foo|foo done”;

break;

…

}

Thats all. Everything else is just building on top of this.

Source : http://news.php.net/php.general/219164