how to show a div when vimeo video reaches certain second?

var iframe = document.getElementById('video');

// $f == Froogaloop
var player = $f(iframe);

// bind events
var playButton = document.getElementById("play-button");
playButton.addEventListener("click", function() {
  player.api("play");
});

var pauseButton = document.getElementById("pause-button");
pauseButton.addEventListener("click", function() {
  player.api("pause");
});

.button {
  width: 48px;
  height: 48px;
  cursor: pointer;
}

.defs {
  position: absolute;
  top: -9999px;
  left: -9999px;
}

iframe {
  float: left;
  width: 350px;
  height: 200px;
}

.buttons {
  padding: 1rem;
  background: #f06d06;
  float: left;
}

body {
  padding: 1rem;
}

.show--div-20sec {
  width: 100%;
  background: red;
  height: 80px;
  float: left;
  display: none;
}

<script src="https://s3-us-west-2.amazonaws.com/s.cdpn.io/3/froogaloop.js"></script>
<iframe src="https://player.vimeo.com/video/80312270?api=1" width="500" height="281" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen id="video"></iframe>
<!-----------Show this div when video has been played for 20 seconds----->
<div class="show--div-20sec">
  Show me after 20 second of video play
</div>


<div class="buttons">


  <button id="play-button">Play</button>
  <button id="pause-button">Pause</button>

</div>