Web Bluetooth

bluetooth.js

const serviceUuid = 0xFFE0, characteristicUuid = 0xFFE1;

document.addEventListener('DOMContentLoaded', () => {
  document.getElementById('connect').addEventListener('click', (event) => {
    event.target.style.display = 'none';

    navigator.bluetooth.requestDevice({
      filters: [{name: 'HMSoft', services: [serviceUuid]}],
    }).then((device) => {
      document.getElementById('form').style.display = 'block';
      device.gatt.connect().
        then((server) => server.getPrimaryService(serviceUuid)).
        then((service) => service.getCharacteristic(characteristicUuid)).
        then((characteristic) => characteristic.startNotifications().
          then(() => characteristic.addEventListener('characteristicvaluechanged', receive))
        )
      ;
    });
  });
});