JSFiddle - React, Tailwind, and code Playground

HTML

<ul id="r"></ul>

<iframe id="ytplayer" type="text/html" width="300" height="200"
  src="//www.youtube.com/embed/M7lc1UVf-VE?autoplay=0&origin=//example.com"
  frameborder="0"/>

JavaScript

var regex = /(?:youtu\.be|youtube\.com|ytimg\.com|youtube-nocookie\.com).*(?:\/|\?v=|\&v=|\?video_id=|\&video_id=)([\w\-_]{11})[^\w\-_]?/ig;

function matches(s) {
    var res = regex.test(s) ? "match" : "no match"
    return res + ": " + s;
}

var $e = $('#ytplayer'),
    attr = $e.attr('src'),
    attr_tostr = $e.attr('src').toString();


$('#r').append("<li>" + typeof attr + "</li>");
$('#r').append("<li>" + matches(attr) + "</li>");
$('#r').append("<li>" + typeof attr_tostr + "</li>");
$('#r').append("<li>" + matches(attr_tostr) + "</li>");