Reveal.addEventListener('ready', function(){
[].slice.call(document.querySelectorAll('ul li')).forEach(function(el){
el.classList.add('fragment');
});
});

function playCurrentFragment() {
  [].slice.call( document.querySelectorAll( '.fragment' ) ).forEach( function( fragment ) {
    var audio = fragment.querySelector( 'audio' );
    if( audio ) {
      if( fragment.classList.contains( 'current-fragment' ) ) {
        audio.play();
      }
      else {
        audio.pause();
      }
    }
  } );
}
Reveal.addEventListener( 'fragmentshown', playCurrentFragment );
Reveal.addEventListener( 'fragmenthidden', playCurrentFragment );