[lj3]

As far as I can tell, pnacl came pretty darn close. It executes LLVM bitcode and supports hardware features like SIMD and threads. For some reason I'm not aware of[0], they made pnacl dependent on the pepper plugin api, which only chrome uses. That pretty much killed it dead on arrival. None of the other browser manufacturers were interested in implementing chrome's pepper api so they can run chrome plugins, especailly since the pepper api isn't open and isn't documented anywhere.

[0]: I'm sure there's a good reason for this decision, I just don't know what it is.

[candiodari]

I would agree. PNacl is one of those technologies that failed because it died, not because it was bad. People felt it needed to be killed and it was killed, or abandoned.

There is criticism, such as that it only solved one part of the puzzle of getting real apps running on the web browser, but it's not like anything else came closer.