We've looked at the origins of MVC and the way it was adapted for traditional server-side web applications. How does it work when we use it with the kind of JavaScript-heavy application we'd typically build using Ext JS?

The whole MVC concept moves entirely into the browser. As far as we're concerned, the server can use any technology it wants. It'll generally just provide and consume data to and from the browser. We move back to an MVC implementation that is a little more like the Smalltalk version (different UI elements you see on-screen are views) and each can have their own controller.

Again, this is about breaking down responsibility. Instead of having a single controller take care of an entire page, we can have a search controller, a list controller, and a detail controller (anything that represents the logical units that make up our application). This is a key detail in how the step from server-side MVC to client-side MVC can help our application architecture.

We already...