SO38461993

<!doctype html>
<html>

<head>
  <meta charset="utf-8">
  <title>Stop YTPlayer</title>
</head>

<body>
  <section id="videoChannels">
    <div>
      <iframe id="yt0" class="player" src="https://www.youtube.com/embed/8IzxdjVr5ZI?enablejsapi=1" frameborder="0" allowfullscreen></iframe>
      <button class='stop' data-id='yt0'>STOP</button>
    </div>

    <div>
      <iframe id="yt1" class="player" src="https://www.youtube.com/embed/AhenpCh6BO4?enablejsapi=1" frameborder="0" allowfullscreen></iframe>
      <button class='stop' data-id='yt1'>STOP</button>
    </div>

    <div>
      <iframe id="yt2" class="player" src="https://www.youtube.com/embed/HrmF-mPLybw?enablejsapi=1" frameborder="0" allowfullscreen></iframe>
      <button class='stop' data-id='yt2'>STOP</button>
    </div>

    <div>
      <iframe id="yt3" class="player" src="https://www.youtube.com/embed/6KouSwLP_2o?enablejsapi=1" frameborder="0" allowfullscreen></iframe>
      <button class='stop' data-id='yt3'>STOP</button>
    </div>
  </section>
  <script>
    var vidCh = document.getElementById('videoChannels');

    vidCh.addEventListener('click', ytCommand, false);

    function ytCommand(event) {
      if (event.target != event.currentTarget) {
        var btn = event.target.getAttribute('data-id');
        var ytp = document.getElementById(btn);
        ytp.contentWindow.postMessage('{"event":"command","func":"' + 'stopVideo' + '","args":""}', '*');
      }
    }
  </script>
</body>

</html>

#UPDATE
OP has multiple players and uses plain JavaScript, the following changes are:

 1. Multiple players shared the same id, now each player has a unique id.
 2. Added a `<button class='stop' data-id='yt*'>STOP</button>` for each player.
    - Each button has a `data-id`. It's value corresponds to it's player's id.
 3. Wrapped `<section id='videoChannels'></section> around everything.
    - Added the `eventListener` to it so when a button is clicked it becomes the `target.currentTarget` initially.
    - After the `capture eventPhase` the event chain reaches `event.target` (the button that was clicked) and the function `ytCommand()` is called on the player that corresponds to the button (see step 2.)

##Working Demo


#Stopping YouTube Player

 1. Access the iframe by using [`contentWindow`][1] method
 2. Next cross-domain communication through an iframe is possible with the [`postMessage` API][2].
 3. Next post commands from [YouTube iFrame API][3]

##Relevant Code

    $('#stop').on('click', function() {
    
      $('#ytPlayer')[0].contentWindow.postMessage('{"event":"command","func":"' + 'stopVideo' + '","args":""}', '*');
    });

##Working Demo

<kbd>[**FIDDLE**][4]</kbd>


  [1]: https://developer.mozilla.org/en-US/docs/Web/API/HTMLIFrameElement/contentWindow
  [2]: https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage
  [3]: https://developers.google.com/youtube/iframe_api_reference#Playback_controls
  [4]: https://jsfiddle.net/zer00ne/3fchv2Ld/