The AJAX technology

As we'll see in this chapter, the name AJAX can be a bit misleading. Every component mentioned in the name Asynchronous communication, JavaScript, and XML is not used exclusively in the technology. We can also use synchronous forms of communication, data formats other than XML, and even use scripting languages other than JavaScript (although the APEX built-in AJAX framework supports only JavaScript).

In the following sub-sections, we'll briefly review some major AJAX concepts that I believe are important to know and understand, in order to better utilize the technology better.

The XMLHttpRequest object

AJAX is based on an HTTP communication between the client side and the server side. The go between is a DOM object called XMLHttpRequest. The object API a series of built-in object methods allows us to generate and use it in a client-side scripting language (in our case JavaScript) in order to send a request to the server and in turn, process the server response and use it...