Usability and Accessibility with AJAX
http://www.sitepoint.com/blogs/2005/03/10/usability-and-accessibility-with-ajax/

Willison, Simon
SitePoint
2005

Abstract:

The Ajax express train rumbles on, threatening to crush anything in its path. Recent discussion has turned to those critical elements of good web development, usability and accessibility. Accessibility is a major issue with Ajax, mainly because anything that relies on JavaScript to function is inaccessible pretty much by default. There are two solutions: either provide a fall-back system where the site remains useful without its Ajax enhancements, or provide a whole separate interface that works without scripting.