This is CPython, the standard Python implementation, compiled from C to JavaScript using Emscripten, running in your browser (without any plugins).

* Most core language stuff should work, except for importing non-static modules (in other words, import sys will work, but other modules won't).
* Please report bugs if you find them!
* Tested on Firefox 4 and Chrome 10.
* The editor is Skywriter.

LINK: http://syntensity.com/static/python.html