Build:
Install emscripten and make sure emcc is in your $PATH.
./buildall
see output for compiled results.

snem port is outdated, can only be compiled by a very old version of emscripten. 
I might update it in future but snes9x seems to be fast enough for modern devices.

snes9x port is updated for emscripten 1.34.3

snes9x is build with sound by default. comment out -Dsound in snes9x/sdl/buildhtml to disable sound.

More information:
http://tjwei.github.com/xnes  # Demo and information (brought your own roms)

Blog posts (Tradition Chinese)
http://weijr-note.blogspot.tw/2012/06/javascript-snes-emulator-wip.html # Orginal version (6/22/2012)
http://weijr-note.blogspot.tw/2012/08/js.html                   # more videos
http://weijr-note.blogspot.tw/2012/08/coscup-2012.html          # COSCUP slides