front-end js and back-end python

[3lnyn0]

Hi!
Can you guide me how can I link pycharm with intellij?

I worked at an app for an interview, I made the back-end part in pycharm with python and flask.
Now I want to create an interface for that app with JavaScript (I'm learning it in this moment JavaScript, I am beginner). My problem it is that I don't know how to make this programs to work together.

Or should I write the front-end code in pyharm in same program? It's a good ideea if I create a folder view and to put there all the code (html and JavaScript, I don't know if PyCharm knows JavaScript)?
Or if you have another ideas how can I create a front-end I am open.

Some tutorials would be very helpful.

Thanks!

P.S. Please without malicious comments!