Integrating AJAX with the Mini HR Application

AJAX Overview

To integrate AJAX with Struts applications, it's necessary to understand in a general way how AJAX works. As stated, AJAX is an acronym that stands for Asynchronous JavaScript and XML. AJAX is not a technology itself, but rather a composite of technologies that are used to perform updates to a web page without requiring the page to be refreshed entirely. The core technologies used to accomplish the updates are JavaScript and XML, thus the acronym (which was coined by Jesse James Garrett).

Architecturally, AJAX is straightforward. JavaScript is used to asynchronously (that is, without refreshing the entire page) make an HTTP request to a server and retrieve data. Typically the data is in XML format, but it can be in any format such as HTML or even plain text. After retrieving the data from the server, JavaScript code then updates a portion of the page it resides in. Thus, this mechanism avoids refreshing the entire page when only a portion of it changes. As a result, more responsive Web-based applications can be built.