The Chromium Web browser (aka Google Chrome) doesn't permit access to file:// by default. You therefore have to enable a command-line option to switch on access. Symptoms are that absolutely no application "works" but when viewing Pyjs applications on the internet (via http://) they work perfectly.
Launch Chrome with the additional parameter --allow-file-access-from-files (or --disable-web-security, if you want to be rude), e.g.
Or you start up a web server on your local system, and use http://127.0.0.1/
Please do not raise a bugreport with Pyjs: it is not our fault.