JerryScript

http://iotjs.net/

http://jerryscript.net/

https://github.com/Samsung/jerryscript

''JerryScript is the lightweight JavaScript engine intended to run on a very constrained devices such as microcontrollers: 1) Only few kilobytes of RAM available to the engine (<64 KB RAM), 2) Constrained ROM space for the code of the engine (<200 KB ROM). The engine supports on-device compilation, execution and provides access to peripherals from JavaScript.''