If you are interested in knowing more about the difference between exchanging data in the XML or JSON format, I would recommend checking the online article "Speeding up AJAX with JSON," which explains in details this subject. This article can be reached here. The author shows how much faster it is to use JSON instead of XML since there will be no construction of the XML DOM tree on the client before being able to access the XML data. Data exchanged in JSON will be nothing but a text human readable data, which can be easily parsed and accessed as a normal object. During this article you will be more introduced to JSON objects, arrays, and other data types and you will see how easy and faster it is to work with JSON especially when we are dealing with web applications AJAX enabled.