On this Hackaday.io and GitHub, we already have plenty of projects about OWON Bluetooth-equipped Digital Meters. Some use Arduino for interfacing BLE, some others use gattlib or other platform-dependent libs.
Recently I tried Web Bluetooth API in my project and found it's really handy for prototyping a multi-platform BLE application. At the same time, I was seeking a data logger to debug my another on-going project.
So as a one-day project which satisfies both means and an end, I decided to write something for my OWON B41T+ BDM.