The AJAX Tag Library is a set of JSP tags that simplify the use of Asynchronous JavaScript and XML (AJAX) technology in JavaServer Pages. AJAX is primarily rooted in JavaScript. However, many server-side developers do not have an extensive knowledge of client-side programming in the browser. It’s much easier in some cases for J2EE developers, especially, to simply add a JSP tag to the page to gain the function desired. This tag library fills that need by not forcing J2EE developers to write the necessary JavaScript to implement an AJAX-capable web form. The tag library provides support for live form updates for the following use cases: autocomplete based on character input to an input field, select box population based on selections made from another field, callout or balloon popups for highlighting content, refreshing form fields, and toggling images and form field states on/off. The implementation is a combination of Java classes and JavaScript source files. The Java code should be OS independent as there are no client side components. However, the Java is dependent on JDK 1.4+ and requires a Servlet container to run. The JavaScript should run in at least Firefox 1.0+ and Internet Explorer 5.0+.
