JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://www.youtube.com/player_api"></script>
<iframe id="player" width="426" height="240" src="http://www.youtube.com/embed/21eGxOKUxeM?enablejsapi=1&origin=*" frameborder="0" allowfullscreen></iframe>

JavaScript

// YouTube API
function player_state_changed(state) {
    alert('state changed');           
    if (state == 1 ) {
        alert('playing...');
    }    
}
var player = document.getElementById('player');
player.addEventListener('onStateChange', player_state_changed);