Very much aligned with React.js approach.

I think it's a very cool idea as this could let the JIT melt together browser code with user code to one tight piece of code.

This is interesting...one of the new javascript frameworks on the block (React.js, http://facebook.github.io/react/) has made use of a 'virtual dom' which basically does a diff and compares it to what was already rendered and then does minimal changes to express the new state based on that.

From what I hear (I have yet to dive into React, although I plan on it) this makes it VERY fast...because the DOM is essentially touched as little as possible directly.

That is really awesome.

FWIW, Firefox has supported something along those lines for a long time, through XPCOM. A little over a year ago, I implemented something slightly more modern for WebIDL in Firefox.

Our approach, and I believe the approach described in these slides, is too heavyweight for things like elements that need to be very high performance, but it is useful for a lot of things.