An extremely useful feature of the Amazon Associates Web Service is argument reflection: any value passed into the service is reflected back, and can be incorporated into any XSL output. This is very valuable to the service’s extensibility. In this case, by inserting a reference to a callback function in our request, it allows us to “tell” our client application what to do with the response it receives from the web service. This aspect of the request will be examined in more detail later in the tutorial. For more information on the construction of REST queries for the Amazon ECS, refer the the Amazon Associates Web Service API Reference Guide.

So far, we have covered the roles of AJAX, JSON, XSLT and REST queries in the Amazon ECS. Next, we’ll start building the application that will parse, transmit and process our REST query.