JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://www.youtube.com/player_api"></script>

<iframe id="player" width="560" height="315" src="https://www.youtube.com/embed/o5rEqjOeKp0?enablejsapi=1" frameborder="0" allowfullscreen></iframe>

JavaScript

var player;
function onYouTubePlayerAPIReady() {
  player = new YT.Player('player', {
    events: {
      'onReady': onPlayerReady,
      'onStateChange': onPlayerStateChange
    }
  });
}
function onPlayerReady(event) {
  alert(event.target.getDuration());
function secondsTimeSpanToHMS(second) {
    var hour = Math.floor(second/3600); 
    second -= hour*3600;
    var minute = Math.floor(second/60); 
    second -= minute*60;
    alert( hour+":"+(minute < 10 ? '0'+minute : minute)+":"+(second < 10 ? '0'+second : second)); 
}
secondsTimeSpanToHMS(event.target.getDuration());
}
function onPlayerStateChange(event) {
  if (event.data == YT.PlayerState.ENDED) {
    alert('done');
  }
}