Chrome 58 supports web bluetooth, compare https://developers.google.com/web/updates/2015/07/interact-with-ble-devices-on-the-web.
Please consider using Web Bluetooth as a synchronisation means between Garmin Connect in the browser and BLE capable Garmin devices. This would make it very convenient for example to sync between Garmin Connect and the Fenix 3 directly from the browser without additional software like Garmin Express. Thanks in advance.