Chrome browser: Cannot launch python code visualizer

Question

Pythontutor , a code Visualizer is integrated within CloudCoder (an open source web-based programming exercise system). When I click on the Visualize button (to the left of the green bar in the screenshot below), only a blank window pops up. The visualizer doesn't show up with the code under question.

This problem seems specific to all browsers (Chrome, Firefox and Opera) running on Windows 7 on a PC (I don't know if it works okay on Windows 8).

To re-create the problem, click on this demo problem available at this URL (userid: guest password: password ). Any ideas on how to get the Visualizer to work within the browser?

Answer 1

It's usually a good idea to check the dev console when anything goes wrong:

The message above is self-explanatory, but unfortunately pythontutor.com does not seem to support HTTPS (it responds, but with a "Forbidden" error page).
You should contact them and kindly ask them to upgrade, if you care about security.
In the mean time, see this question & answer for how to work around security:
How to allow http content within an iframe on a https site

(The problem isn't specific to Windows btw, I'm running OS X 10.10.5 with Chrome 48 dev.)

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An entirely different approach in this particular case would be to simply get the PythonTutor source code and host it yourself.