The simple REPL provides a limited Python experience in the
browser.
Platforms/emscripten/README.md
contains a list of known limitations and issues. Networking,
subprocesses, and threading are not available.
SharedArrayBuffer, which is required for this demo,
is not available in your browser environment. One common cause
of this failure is loading index.html directly in
your browser instead of using server.py as
described in
Platforms/emscripten/README.md
.
For more details about security requirements for
SharedArrayBuffer, see
this MDN page.