Add buffering bar in audio player

[Azzimi]

I'm working with HTML5, making an audio player.I wonder to know how I can add a buffer bar so that the user can see how long the song is loaded.I've tried using several properties that I saw in some tutorials, but none have worked, and I can not find anything about this specific topic.This is the audio player that I'm trying to edit.I wish someone could guide me on how to edit the code to do it, or, otherwise, recommend tutorials, documentation or any information.