How do I make an <audio> file play continuously on all pages?

Question

I am wondering how I make get an audio file to play 'continuously' on all pages. So if the audio file has played for 20 seconds, then when navigating on another page it will continue from where it left off. I also am trying to get the volume to decrease after navigating away from my home page. Any tips or advice would me appreciated! Thanks =D

<audio src="songforsite.mp3" loop="true" autoplay="true" controls> Unsupported in Firefox </audio>