Access game here: https://vanillajschess.github.io/
This is a chess engine/algorithm made only with vanilla JS, CSS, HTML.
The engine itself is okay but makes some mistakes. Probably would be rated under 1300.
Hopefully this project displays what you can do without libraries or frameworks.
There are a lot of inefficiencies in the project that you are welcome to improve. I'll take any constructive criticism you have.