Ajax stands for Asynchronous JavaScript and XML. In a nutshell, it is the use of the nonstandard XMLHttpRequest object to communicate with server-side scripts. Ajax's most appealing characteristic, however, is its "asynchronous" nature, which means it can do all of this without having to refresh the page. This allows you to update portions of a page based upon user events and provides one of the cornerstones of Rich Internet Applications (RIA) referred to in discussions of "Web 2.0".

Prototype is one of the most known JavaScript libraries. It doesn't provide custom widgets or elaborate visual effects. Instead, it just strives to make JavaScript more pleasant to work with. In many ways, Prototype acts like the missing standard library for JavaScript

AjaxCore is an open source PHP framework that aims the ease development of rich AJAX applications, using Prototype's JavaScript standard library. This means it uses Prototype as the core for making the AJAX requests, as it's proven to be reliable on any browser, plus adding all Prototype's features and shortcuts that reduce typing and help avoid the reinvention of the wheel.

The framework is really easy to use, you can start using AjaxCore right away as it doesn't require you to learn anything new. All functionality is build into a PHP class file that you'll have to extend with your custom requirements, and then bind HTML elements with PHP functions that will called when the appropriate JavaScript event is triggered, thats all you have to handle, also optionally you may send HTML elements by just attaching their IDs and the framework will do the rest.

AjaxCore works either on PHP4.x or PHP5.x, the package contains two classes one for each flavor. Although is advised to switch to PHP5 as it supports classes natively.

As your application gets complex, typically, the application code is separated from the the presentation using templating frameworks that encapsulates presentation into tpl files. This functionality does not interfere with AjaxCore, as the headers needed for the framework can be easily placed into tags on the tpl file, and then replaced with the templating engine.