the acronym for Asynchronous JavaScript and XML

a DOM* that is accessed with JavaScript to dynamically display, and to allow the user to interact with the information presented

* DOM – document object model

DOM (document object model) is a strategic and open effort to specify how to provide programming control over documents.

Source: w3schools.com/ajax

Classic (static) web pages, (which do not use AJAX) must reload the entire page if the content should change.

Examples of applications using AJAX: Google Maps, Gmail, Youtube, and Facebook tabs.

Render Logo

Render Section 1

Download File (Part 1)

Download File (Part 2)

Render Section 2 from file.

Render Section 3

Blocking could occur here delaying the rendering of Section 3

Render Logo

Render Section 1

Download File (Part 1)

Download File (Part 2)

Render Section 2 from file

Render Section 3

Allows us to download information from a server on an as needed basis.

Instantiate an XMLHTTPRequest object

Danger, Will Robinson, Danger!

Danger, Will Robinson, Danger!

if(browser == "Microsoft Internet Explorer"){

objAjax = new ActiveXObject("Microsoft.XMLHTTP");

if(browser == "Microsoft Internet Explorer"){

objAjax = new ActiveXObject("Microsoft.XMLHTTP");

if(browser == "Microsoft Internet Explorer"){

objAjax = new ActiveXObject("Microsoft.XMLHTTP");

getElementById must match the area of the browser that you are targeting.

State Description

0 not initialized

1 set up

2 sent

3 in progress

4 complete

A request will go through a series of states on the way to completing the request

A small section of a page can be updated. Saves on bandwidth and loading times, and reduces server load.

The code is lightweight and not very complex.

JavaScript and the XMLHttpRequest object are supported in all modern browsers

It's got the geeky cool factor ;-)