Figure 2

The AJAX Framework

Like most web services, Amazon’s Web Service API is based on AJAX[1], short for Asynchronous JavaScript and XML,which combines the technologies of HTML, JavaScript and XML to allow a client application to asynchronously communicate with a web server without interrupting the client’s code execution (e.g., data transference and updating between a browser and a service provider like Amazon will appear to take place seamlessly to the user). To help understand the process, let’s examine the different parts.

The HTML component primarily controls the final presentation of information and consists of (X)HTML and CSS languages (although other languages can be used).

The XML component consists of XML, XSL and XSLT to handle the transference, manipulation and transformation (or display) of information.

Asynchronous transfer of information & interaction between a web server and a browser occurs via the Document Object Model and its construct, XMLHttpRequest.

JavaScript is the language through which the other AJAX technologies can interact.

Although in theory, AJAX functions to provide a seamless interaction between a server and browser, in practice, there is a price that an AJAX developer must pay for that functionality – security.