[meredydd]

There are actually quite a few Python-in-the-browser implementations, not just those two! A couple of years ago a colleague of mine wrote up a comparison, including Brython and Pyodide:

https://anvil.works/blog/python-in-the-browser-talk

(We chose one of the Python-to-JS compilers, https://skulpt.org, for the Anvil web-app platform, because it's much lighter weight than this. It's a couple of hundred kb on the wire, and you can call to the server for any heavy lifting.)

[pjmlp]

And before all of those, 20 years ago, ActiveState had a Python ActiveX extension (in addition to Perl and TCL).

[nacs]

Just the word "ActiveX" brings about nightmares.

[rmbyrro]

One downside with python-to-js compilers is losing easiness and speed to debug issues, which is one of the strongest points for using Python.

[eatonphil]

It also requires a server somewhere for dynamic input (i.e. Browser based notebooks).