// ==UserScript==
// @name youtube-force-html5
// @namespace youtube-force-html5
// @include https://www.youtube.com/*
// @version 1
// ==/UserScript==
// No Flash + youtube-nocookie embed =
// Forces Youtube to display HTML5 player
if(confirm('Html5?')) {
x = document.URL.split('/');
x = x[x.length-1].split('?v=');
x = x[1].split('&');
url = 'https://www.youtube-nocookie.com/embed/'+x[0];
document.location = url;
}