Mako.js is a JavaScript implementation of Mako, a virtual game console. An interactive gallery of Mako programs can be found here.
Specifying a rom argument to the gallery URL can link to a specific Mako rom:
http://johnearnest.github.io/Mako.js/?rom=Yar
Command-line (CO IO only) Mako programs can be run locally with Node.js:
$ node MakoCLI.js roms/testcli.rom
Hello!
Please enter some text: For Example...
You entered 'For Example...'
Have a nice day.
$
Note that while character input from stdin does not work in the current release version of Node (at time of writing v0.10.31) it does work with v0.11.13.