The Atlas framework has two distinct elements - a client script framework, and a set of server extensions that integrate Atlas with ASP.NET. The client script framework is 100% Javascript, and works with any modern browser. But it is also completely server-agnostic, and works with any web server.

http://www.shankun.com/AtlasPhp.aspx

ref: http://weblogs.asp.net/scottgu/archive/2006/03/29/441357.aspx