The new tendency in the last deacades in software development is the "rich Internet application". To be close to desktop application, you should have some advanced web
graphic tools and frameworks. Extjs has all the features to allow you to develop your rich Internet application.
The predefined tools such us grid, forms, panels and menus are rendered client-side.You don't have to wonder about compatibility. It's designed to work perfectly on any common browser.
Coding and editing Ext js scripts is fun. Since there are many examples with the downloaded package of the library and it has a very helpful community. These are some Screeshots of what this library is capable of: