Replace old Flash Player-based YouTube embeds by their new HTML5 counterparts

Ideal if you don't have Flash Player installed in your device. I know I don't.

You will need to install an extension such as Tampermonkey, Greasemonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install an extension such as Tampermonkey or Violentmonkey to install this script.

You will need to install an extension such as Tampermonkey or Userscripts to install this script.

You will need to install an extension such as Tampermonkey to install this script.

You will need to install a user script manager extension to install this script.

(I already have a user script manager, let me install it!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(I already have a user style manager, let me install it!)

// ==UserScript==
// @name        Replace old Flash Player-based YouTube embeds by their new HTML5 counterparts
// @description Ideal if you don't have Flash Player installed in your device. I know I don't.
// @namespace   greasyfork.org/users/4813-swyter
// @include     *
// @version     2016.01.03
// @noframes
// @grant       none
// @run-at      document-start
// @icon        https://i.imgur.com/L2y0zMj.png
// ==/UserScript==

/* wait until the page is ready for the code snipped to run */
document.addEventListener('DOMContentLoaded', function()
{
  /* iterate over all the existing SWF Youtube players in the page */
  for (var cur in (vids=document.querySelectorAll('object > embed[src*="youtube"]')))
  {
    console.log(vids[cur], typeof vids[cur]);

    /* create the HTML5 player element */
    iframe = document.createElement('iframe');
    iframe.src = 'https://www.youtube.com/embed/' + vids[cur].src.split('?')[0].split('/')[4];

    /* keep their same size */
    iframe.width = vids[cur].width;
    iframe.height = vids[cur].height;

    /* no borders plz, thanks! */
    iframe.setAttribute("frameborder", 0);

    /* replace the old SWF Flash object with it, voilà */
    vids[cur].parentNode.parentNode.replaceChild(iframe, vids[cur].parentNode);
  }
}, false);