Greasemonkey Script to add "Couch Mode" to YouTube

youtube_couch_mode.user.js

// ==UserScript==
// @name		YouTube Couch Mode
// @author		David Wittman <david@wittman.com>		
// @namespace		nowhere
// @description		Adds a full-screen "Couch Mode" button to YouTube
// @include		http://www.youtube.com/watch?*
// ==/UserScript==


// iframe detection
// http://stackoverflow.com/questions/1535404/how-to-exclude-iframe-in-greasemonkey
if (window.top != window.self) {
	return;
}

(function() {
	var ytBase = 'http://www.youtube.com/v/';
	var ytPattern = /&?v=([-_A-z0-9]+)/;
	var flagBtn = document.getElementById('watch-flag');
	var couchMode = document.createElement('button');
	var videoId = ytPattern.exec(window.location)[1];;
	
	couchMode.innerHTML = '<span class="yt-uix-button-content">Couch Mode</span>';
	couchMode.className = 'yt-uix-tooltip-reverse yt-uix-button yt-uix-button-default yt-uix-tooltip';
	couchMode.setAttribute('data-tooltip-text', 'Watch in full window');
	
	flagBtn.parentNode.insertBefore(couchMode, flagBtn);
	
	bind(couchMode, 'click', function() {
		window.location = ytBase + videoId;
	});

	function bind(obj, event, fn) {
		if (obj.addEventListener) {
			obj.addEventListener(event, fn, false);
			return true;
		}
		else if (obj.attachEvent) {
			var r = obj.attachEvent("on"+event, fn);
			return r;
		}
		else {
			return false;
		}
	}
}
)();