Setting variable values in JavaScript files
It is not possible, as Javascript usually runs on the client side, while Python runs on the server side.
If it is code that needs to run on the client side, have it send an AJAX request to a python script with the results you need. If it does not need to run on the client side, I suggest you rewrite it in Python.
I have a Python script and a JS on my server. In the python script, I want to set the value of a variable to be the output of one of the functions in my .js file. 
Is this possible, and if so how wold one go about doing this?
Thanks!