A generalized, dynamic-language friendly bytecode to replace Javascript would be great. Please let me choose to use Python for client-side web without resorting to language cross-translation hacks.
Find the commonalities between Ruby, Python and Javascript and such (there are a lot!) and base the VM on that. "Legacy" javascript can then run in the existing VM. For JS, people can choose to compile it or let the browser compile it.
On the other hand I don't like NaCL at all. Even with all the security measures, there is just too much risk in executing native code directly from the web. Also it splits up platforms, splitting the client world into x86 and ARM, instead of allowing for innovation in CPU-land by exposing are more abstract interface. It is a repeat of the "browser plugin" paradigm, which luckily failed.
Find the commonalities between Ruby, Python and Javascript and such (there are a lot!) and base the VM on that. "Legacy" javascript can then run in the existing VM. For JS, people can choose to compile it or let the browser compile it.
On the other hand I don't like NaCL at all. Even with all the security measures, there is just too much risk in executing native code directly from the web. Also it splits up platforms, splitting the client world into x86 and ARM, instead of allowing for innovation in CPU-land by exposing are more abstract interface. It is a repeat of the "browser plugin" paradigm, which luckily failed.