The demand for increased interactivity with today’s web applications has resulted in a need to bring the familiar UI features of the desktop to the Web. With the availability of mature 3rd party JavaScript libraries, AJAX technology (DOM, CSS, JavaScript) provides a feasible way to fill this need. The presenter will walk through building rich web apps using Yahoo! UI (YUI) and Ext JS JavaScript libraries on the Grails platform. The presenter will also demonstrate ways of implementing basic and advanced features using these libraries.