Does your localhost have Python installed? I think that would help in making sure your localhost and your "real" server will deliver the same results.

To answer your original question, as far as I know, Firefox does not have a built-in interpreter for Python the way it does for JavaScript.

Python is installed on my localhost. I can use it in a terminal window, but I think you provided the explanation as to why it does not work when I call it in Firefox.

You might just need to add something to your localhost webserver's config files to point it to the python interpreter. But I have no idea how you do it.