Ruby / Sinatra Ajax重型应用程序How-Tos

I am planning to create a single page, where a user can load his data and manipulate it. It should have a very desktop-like feel (slick driven by ajax). I evaluated some javascript widget frameworks and decided to try out ExtJS (although any other recommendations would be welcome as long as it supports some sort of a Grid/Table/Cell element this is absolutely a must).I am planning to create a single page, where a