HTML & simple jQuery to display and autoplay a YouTube video after a button/link has been clicked. There is more magic that displays the content but that is for another gist. This just sets the URL of the iframe and starts the video.

playvideo.html

<figure class="video">
  <iframe id="video-player" data-videoid="du4Y4KtGXBg" src="" frameborder="0" allowfullscreen></iframe>
</figure>

playvideo.js

  // Display the video
  var youtubeID = $('#video-player').data('videoid'); // get the video id from the data-attribute
  var youtubeURL = "//www.youtube.com/embed/" + youtubeID + "?autoplay=1"; // build the url
  $('#video-player').attr('src', youtubeURL); // set the url
  $("figure.video").fitVids(); // Use FitVids to size the videos. (http://fitvidsjs.com/)