The Many Layers of Ajax
by Justin Gehtland

The term "Ajax" was born on February 18, 2005, in a white paper called
"Ajax: A New Approach to Web Applications" by Jesse James Garrett of
Adaptive Path. At the time, Ajax meant Asynchronous JavaScript and XML,
but it isn't really an acronym anymore. Today Ajax code doesn't
require XML, and it needn't be asynchronous. Instead, Ajax means
writing highly interactive Web applications that deliver a richer user
experience than traditional versions. It means taking advantage of
JavaScript and an object called XMLHttpRequest (XHR) to send requests
to the server and bypass the traditional link-or-submit ways of
interacting with a Web server. And it means getting results from those
requests and using them to update parts of the page. So don't worry
about the official definition of Ajax. It is really a combination of
old technologies like DHTML, JavaScript, and CSS, with the magic fairy
dust of XHR sprinkled on top.

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