Ajax Tradeoffs: The Many Flavors of XML
http://www-128.ibm.com/developerworks/web/library/x-matters48/

Elza, Dethe and David Mertz
IBM
2007

Abstract:

Ajax stands for Asynchronous JavaScript and XML and the idea is that with modern Web browsers you can, with acceptable reliability, keep a channel open to the server to pass data back and forth as your Web application is used. This contrasts with standard Web techniques that follow links, causing the entire page to load anew. Many aspects of Ajax-based development require design different decisions than traditional Web pages: How to manage the back button, how to display updated data, how often to send updates, and more. The focus for now will be on just one group of related aspects: what format should the data exchange take?