JerryScript

If I had known this script in my university period I would be happy to use it for my microcontrollers projects. It's quite lightweight and uses only few Kbs.

Github

JerryScript is the lightweight JavaScript engine intended to run on a very constrained devices such as microcontrollers:

• Only few kilobytes of RAM available to the engine (<64 KB
• Constrained ROM space for the code of the engine (<200 KB ROM)
  Source