var list = document.getElementsByTagName("audio");
  for (var i = 0; i < list.length; i++) {
    list[i].addEventListener("play", function(e) {
      var filepath = e.target.src;
	  var pattern = 'uploads/';
      var label = filepath.substr(filepath.indexOf(pattern) + pattern.length);
	  gtag('event', 'play',
        { 'event_category': 'blog', 'event_label': label }
  	  );
	});
  }