Rich UI framework

Everyone has embark into Web 2.0 era. With the aid of available framework, developer can easily enhance web application with rich user-interface. Rich UI is achieved by Ajax functionalities. ExtJs, icefaces, google GWT are the common and consist of relatively full suite of powerful component which speed up the development of web application. ExtJs make up of javascript codes which allow developer to describe the UI "swing style" in javascript. With ExtJs framework, UI and back-end are clearly separated. It means that client browser will do the render of UI and the server does the pure data processing. For that, UI can consider as a skin for the web application and can be modified without changes in the back-end code. For team development, design and programming task can be divide and not dependent of one another.
Icefaces JSF framework allow programmer to create template in Jsf format. And after compilation, javascript and html are automatically created for the web application. It it easier for JSF developer to integrate icefaces. However the cons are control of the html Dom component is limited. Quite tedious for developer who required to customize the html. Google toolkit GWT allow developer to create UI using "swing" java codes. Upon compile, javascript and html will be generated automatically. Since the UI is described in java, java features can be utilized and more robust. But the trade off is the compilation take time. Every change in UI required a re-compile.