The Xajax PHP class library provides a means to develop asynchronous Ajax applications with PHP
Only tag those questions which deal with the Xajax library and that would normally be accompanied by a JavaScript and/or PHP tag.
Xajax allows PHP coders to formulate complex Ajax transactions from within their PHP code, once placeholders have been created in HTML views.
Official website: http://www.xajax-project.org
On the official website, you will find Javadoc style documentation, and a community forum.
There are some helpful tips and tutorials as well as some demo applications to get you started.