Asynchronous JavaScript and XML (Ajax) / Web 2.0

Web 2.0 – a term associated with the new suite of web applications.
Ajax – a way of making those applications work.
Web applications – where the browser delivers a piece of software that acts more like a program you’d run on your desktop. In the past we’ve been used to a static web page where you fill in information, submit the page and then receive information back from the server as a whole new page. With Web 2.0 applications wanting to mimic desktop applications, parts of a web page needed to be able to change without sending the whole page to the server. Enter Ajax as the methodology.

Ajax is a way of sending chunks of information to the server and receiving responses back without reloading the whole page.

For more information on Web 2.0 and Ajax, see the Definitions section below.

Accessibility issues with Ajax

There are the same accessibility issues with the use of Ajax as any other site that uses JavaScript, just more so. Usually a page using Ajax is completely reliant on JavaScript for its functionality. Turn JavaScript off and the page doesn’t work. So redundancy needs to be built in.

As Ajax manipulates part of the page without needing to rely on reloading the full page, a fallback would be to have the whole page reloading when Ajax fails. Users with Ajax get the bells and whistles; users without still get the content, just in a clunkier format.

There are issues with screen readers and certain Ajax applications. The author of an interesting article on Sitepoint isolated parts of code associated with the refreshing mechanism and tested those with a screen reader. The conclusion was:

“..unless a way can be found to notify screen readers of updated content, AJAX techniques cannot be considered accessible, and should not be used on a production site without a truly equivalent non-script alternative being offered to users up-front.”

All of the usual website Accessibility rules apply as well. Alt-text for images, keyboard access to all page elements and so on. Some Web 2.0 application developers seem to have lost sight of this. With GMail at least, there is no keyboard support in the Ajax version.

The fact that it is Ajax with a fancy name and is associated with delivering the hip ‘n trendy suite of applications dubbed Web 2.0 doesn’t mean the basics can be lost. It just means that you need to put in code to make it work if JavaScript isn’t supported, and follow the usual ‘make it work with a keyboard and follow the rest of the WCAG guidelines’ rule.

Most methods of Ajax rely on modern graphical browsers.

So what’s important?

Follow the WCAG. It’s all there. See Joe Clark’s talk on Ajax for a nice wrap up of the specific guidelines associated with scripting.

Definitions

AJAX: Asynchronous JavaScript And XML, or its acronym, Ajax (Pronounced A-jacks), is a Web development technique for creating interactive web applications. The intent is to make web pages feel more responsive by exchanging small amounts of data with the server behind the scenes, so that the entire Web page does not have to be reloaded each time the user makes a change. This is meant to increase the Web page's interactivity, speed, and usability. (ref: Wikipedia)

Web 2.0: generally refers to a second generation of services available on the World Wide Web that lets people collaborate and share information online. In contrast to the first generation, Web 2.0 gives users an experience closer to desktop applications than the traditional static Web pages. (ref: Wikipedia)

Web 1.0 static web pages with information on
Web 1.5 Content Management System (CMS) driven websites that allow users to manipulate information
Web 2.0 fully responsive web applications that mimic desktop programs – and also allow users to store and share information across the network

Before you had a CMS to effect changes in a webpage, now you have a Wiki which allows you to go right in and make the changes directly. Before you had a personal website, now you write in your blog on MySpace. That’s Web 2.0. The association with Ajax is more to do with delivering some, but not all aspects of these web applications. Google maps uses Ajax, many Wiki-driven pages do not.