Try it here: https://codingwith-adam.github.io/gamepad-tester/
YouTube Tutorial: https://youtu.be/tQyrpcOK6U0
In this exciting tutorial we are going to learn how to use the JavaScript Gamepad API. With this API we are going to build our very own gamepad tester. A gamepad tester allows you to diagnose and figure out if anything is wrong with your controller.
https://developer.mozilla.org/en-US/docs/Web/API/Gamepad_API