getElementsByClassName

HTML

<div class="mute">div 1</div>
<div class="mute">div 2</div>
<div class="mute">div 3</div>

JavaScript

(function() {

	var player_frames = document.getElementsByClassName('mute');
  
  console.info('player frames: ', player_frames);
  
  for ( var i = 0; i < player_frames.length; i++ ) {
  	console.info('player_frames['+i+']',player_frames[i]);
  }
  
})();