The Physical Web project has a web page where they invite you to use a web page to configure your Eddystone beacon. Unfortunately, it doesn’t work for most beacons. The reason is because it assumes your beacon conforms to the new Eddystone Configuration GATT Service that became available in April 2016. Most beacon firmware pre-dates this so isn’t compatible.
A few manufacturers have added support for the new GATT Service. For example, Sensoro that we stock, can be irrevocably turned into what Sensoro call Standard Eddystone GATT that turns the beacon into a generic Eddystone beacon with no Sensoro (or iBeacon) facilities. Even when we did that, the Web Bluetooth Configuration Page wouldn’t recognise the beacon so we suspect the page doesn’t fully work yet.
In the meantime, if you want to configure a beacon having the Eddystone Configuration GATT Service, the best way is to use the Nordic nRF Connect app that does a great job of recognising and describing and configuring the Eddystone Configuration GATT Services.