jjax is a collection of tools and libraries which assist in the development of fat-client style Web applications. jjax provides client-side JavaScript language extensions that greatly simplify usage of the W3C DOM, as well as communications library code that encapsulates XMLHttpRequest calls. jjax also includes Java-based server-side components that perform AJAX request dispatching, JSON data marshaling, and glue code for using the Jetty HTTP library as an alternative to an application server.