How to organize communication between Python and Javascript?

Question

Python

Hello, I am a beginner web programmer with little experience, I started writing a project, an anonymous chat on web sockets.
I chose JavaScript as the client side and Python as the server side. And then came the period of problems. For quite some time now, I have been unable to implement communication between the server and the chat, i.e. there is already a chat, it works fully ... I will give an example. In my chat, there is a demonstration online by displaying a message, i.e. someone logged in writes 'online 2', someone logged out 'online 1', but you yourself think... If you're online, let's say 200, will it flood online chat every millisecond? And so I decided to make a conversation. And a new period has come, a period of questions. And now I ask the toaster for help :3
I forgot to describe the problem. I need a variable with online to be returned from the server.
I have a variable with which I display as a message, but I need to display this variable in JavaScript, and then display it not in a chat, but in a field, any.
Here is the link to the chat 5.101.115.43 (Not advertising)