The page-reload cycle presents one of the biggest usability obstacles in Web application development and is a serious challenge for Java™ developers. In this series, author Philip McCarthy introduces a groundbreaking approach to creating dynamic Web application experiences. Ajax (Asynchronous JavaScript and XML) is a programming technique that lets you combine Java technologies, XML, and JavaScript for Java-based Web applications that break the page-reload paradigm.

One of the features I find it interesting in Google calendar is the possibility to create shared calendars, but also the availability of your calendar as XML or ICAL whatever it's a private or public one. As soon as we have XML of our calendar available I was wondering why not integrating Google calendar directly in website. For example a community that use the service to manage their events, or to display your future trips in your blog

In the previous example, after the response to the HTTP request was received we used the responseText property of the request object, which contained the contents of the test.html file. Now let's try the responseXML property.

First off, let's create a valid XML document that we'll request later on. The document (test.xml) contains the following:

Indeed, it isn't shocking news that AJAX has introduced considerable changes within the development of client-side Web applications. This brand new way of conceiving web programs, which send http requests in the background without page reloads, has brought a plethora of possible implementations for popular software that originally was designed and developed for running as desktop applications.

I just recently discovered the joys of JSON after reading about it for months.  As the SecretGeek puts it:
Two months ago you'd never heard of JSON

1. One month ago you'd heard the term but paid no attention
2. One week ago you'd heard it mentioned a few times and started to think, right... some more crap to learn
3. Today you woke up with an alarm bell ringing in the back of your mind that said WHAT THE BLOODY HELL IS THIS JSON THING AND WHY IS IT EVERYWHERE ALL OF A BLOODY SUDDEN!
   

So what is JSON?  JSON stands for JavaScript Object Notation and is basically a lightweight way of describing hierarchical data.  Since it is so lightweight, it makes it an ideal candidate for AJAX applications.  So what does JSON look like.  The JSON code our JSON AJAX Chat application will be returning will look something like this: