Why not? The DOM is, ultimately, just HTML. The VM state is just data in RAM, which should be eminently serialisable.

I'd think it's the sort of thing which ought to be child's play.

The VM state isn't that easy when you remember that JS can keep open sockets to other things, can launch processes, etc.

Sure, you could find a way to serialize it, but that'd be a lot harder — you can't hust go back to halfway the middle of receiving something through a socket.

One could just close open connexions — after all, a network connexion can always die anyway.

I really hope that JavaScript in a browser can't launch processes!