For websites you make for Tor, you would typically go for PHP or OpenResty, as it needs to be JavaScript-free. I personally aim for JavaScript-free projects regardless.
Of course if you want client-side whatever, you need JavaScript.
JavaScript is optional even on the client side nowadays with the advent of PyScript via WASM, etc.
I did not know that. Is it true? Can I have dynamic updates (something like what AJAX does) without refreshes? If so, I need to do some research in this area! I assume I can use any programming languages for WASM as well?