; Sample
var gatt = device.gatt;
if (gatt) {
gatt.onservicechanged = function onServiceChanged() {
; Sample
var gatt = device.gatt;
if (gatt) {
gatt.oncharacteristicchanged = function onCharacteristicChanged(evt) {
; Sample
var gatt = device.gatt;
if (gatt) {
gatt.onconnectionstatechanged = function onConnectionStateChanged() {