Page_Visibility_API.js

//@@ I don’t want to listen to your music when I switch tabs

var track = new Audio('./darkhast.mp3');

function isVisible (e){
		document.title = document.hidden ? 'please come back and enjoy your music' : 'Enjoying!';
		return document.hidden ? track.pause() : track.play();
}
document.addEventListener('visibilitychange',isVisible);

//For more please :- 
// https://www.html5rocks.com/en/tutorials/pagevisibility/intro/
//https://developer.mozilla.org/en-US/docs/Web/API/Page_Visibility_API