JSP Controls Tag Library (the “Library”) allows building dual-mode JSP components that work in both AJAX and standard mode off the same codebase. The portlet-like components handle input and render output in decentralized manner, therefore a central controller or other coordinator like a portal engine is not required.

The Library utilizes two request processing concepts:
• Redirect-After-Post for synchronous HTTP request/response cycle (non-AJAX mode), and
• In-place update for asynchronous request/response cycle (AJAX mode).

JSP components take advantage of AJAX mode whenever possible. If Javascript or XMLHTTPRequest object is not supported, the components fall back to standard synchronous mode, with no visible degradation of  user expereince. Switching Javascript on and off is possible during interaction.

Pages composed with the Library look and behave the same way whether they run in AJAX mode or in traditional synchronous mode. In fact, a browser that renders web page in an off-screen buffer, may deliver the same flicker-free experience in non-AJAX mode as other browsers do in AJAX mode.

System Requirements
• Java SDK 1.4.2+
• Servlet container, supporting servlet specification 2.3+ and JSP specification 1.2+ (for example, Tomcat 4)
• Browser supporting either bare HTTP 1.1 (for standard mode) or Javascript + XMLHTTPRequest (for AJAX mode).

More information is available on the project page at www.jspcontrols.sourceforge.net