Python example remote.py/remote.html doesn't work in Firefox

[pgagarinov]

Bug Report

Steps to Reproduce:

1. run remote.py script from python\perspective\examples subfolder (I had to remove #sys.path.insert(1, os.path.join(os.path.dirname(__file__), '..')) line though as it is not necessary if perspective from conda-forge is used

2. try to open http://localhost:8888 in Firefox page opens but no data is shown

3. open the console to see the following

Expected Result:

In chrome-based browsers (tested in Brave) everything works

Environment

Firefox 78.0.1 Perspective 0.5.1 from conda-forge

[timkpaine]

1. is required for a local development build so not an issue

[texodus]

Can't repro, this has likely bit-rotted. In general, while I do want to fix any obvious errors on web platforms like Firefox, as we cannot currently run our test suite on this platform, it is not technically supported.