Comment by mm_alex

Imma just gonna leave this here: http://hulkholden.github.com/n64js/ fully functioning n64 emulator in javascript, which dynamically recompiles mips asm to js so that your browser can JIT it into native code. the dev blog is full of amazing js perf knowledge too: http://n64js.blogspot.co.uk/ (videos here also if you dont have any roms to hand)

source code on github. full disclosure: I work with paul, he's very clever.