SproutCore makes it easy to build real applications for the web using menus, toolbars, drag and drop support, and foreign language localization, but it also provides a full Model View Controller application stack like Rails (and Cocoa), with bindings, key value observing, and view controls.
A key component of its clean MVC philosophy that roots SproutCore into Cocoa goodness is bindings, which allows developers to write JavaScript that automatically runs any time a property value changes. With bindings, very complex applications with highly consistent behavior can be created with very little “glue” code.