Get Matched Query String

HTML

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>
<div class="flex-active-slide">
  <div class="video-container" id="video-container">
    <iframe src="https://www.youtube.com/embed/jebJ9itYTJE" frameborder="0" allowfullscreen=""></iframe>
  </div>
</div>
<a class="playButton">play</a>

JavaScript

$(".playButton").on('click', function() {
  $(".flex-active-slide iframe")[0].src += "?autoplay=1";
  $('.flex-active-slide').contents().find("iframe").attr('src', function(i, oldSrc) {
    var isAutoPlay = oldSrc.match(/autoplay=([^&]*)/);
    if (isAutoPlay && isAutoPlay[1] == 1) {
      return oldSrc.replace('autoplay=0', 'autoplay=1');
    }

  });
});