via http://www.emucr.com/

1964js SVN r294 is released. 1964js is the first N64 emulator written in JavaScript (CoffeeScript to JS). It is loosely a port of our N64 emulator for Windows called 1964. 1964 was written in C and C++.

1964js SVN Changelog:
r294
optimizations
r293
and more core performance optimizations
r292
core performance optimizations
r291
core performance optimizations

http://1964js.com/