Repository: https://github.com/robatwilliams/webhid-demos
WebHID awesome list: https://github.com/robatwilliams/awesome-webhid
WebHID is available behind a flag in Chrome 78, which is currently in beta (download here). Enable it at chrome://flags/#enable-experimental-web-platform-features . Check Chrome Platform Status for latest information.
If anything doesn't work, check the console for errors.