JSFiddle - React, Tailwind, and code Playground

HTML

<h2>Видео контент номер 1</h2><span class="time"></span>
<video id="myvideo" width="480" height="270" autoplay>
    <source src="http://doktorpull.myjino.ru/uploads/files/1388073459_pixel-news-v1.mp4">
</video>

JavaScript

(function(window) {
    var videoNode = window.document.querySelector('#myvideo');
    var timeNode = window.document.querySelector('.time');
    videoNode.addEventListener('loadedmetadata', function(e) {
        var duration = videoNode.duration.toFixed(1);
        var m = duration % 60;
        timeNode.innerText = Math.floor(duration / 60) + ':' + (m < 10 ? '0' : '') + m;
    });
})(window);