YouTube - Always Theater Mode

Set the default viewing mode to Theater Mode.

As of 2015-06-19. See the latest version.

// ==UserScript==
// @name        YouTube - Always Theater Mode
// @namespace   r-a-y/youtube/theater
// @description Set the default viewing mode to Theater Mode.
// @include     http://www.youtube.com/watch*
// @include     https://www.youtube.com/watch*
// @version     1
// @grant       none
// ==/UserScript==

document.getElementById('page').className = "watch watch-stage-mode";
document.getElementById('player').className = "content-alignment watch-medium";
document.getElementById('watch7-container').className = "watch-wide";
document.getElementById('watch-appbar-playlist').setAttribute('style', 'top:520px');