Userscripts.org

// ==UserScript==
// @name        Youtube Video in High Quality
// @description View every youtube video in high quality and adds a download link to every video. Right Click on "Download Video" then click "Save As". Video is downloaded in mp4 format encoded in H264 and AAC stereo.
// @author      Keshav Gupta
// @namespace   http://tech-peep.blogspot.com
// @version     1.0
// @include	http://youtube.com/watch?v=*
// @include	http://*.youtube.com/watch?v=*
// ==/UserScript==

if(document.location.href.search(/\&fmt=18/)==-1)
{
   document.location.href = document.location.href + '&fmt=18';
}

var scrhead = document.getElementsByTagName("head")[0].getElementsByTagName("script");

function addBox(strR) {
	var URLDLbox = document.createElement("a");
	URLDLbox.className = "action-button";
	URLDLbox.setAttribute("style", "width:auto !important; color: rgb(0, 51, 204) !important; display: block !important; height: 25px !important; margin-top: 6px !important; margin-left: 1px !important; outline-color: rgb(140, 172, 26) !important; outline-width: 1px !important; visibility: visible !important; float: left !important;");
	URLDLbox.href = strR;
	URLDLbox.id = "GMdownloadButton";
	dlb1 = document.createElement("span");
	dlb1.className = "action-button-leftcap";
	dlb1.setAttribute("style", "vertical-align:");
	URLDLbox.appendChild(dlb1);
	dlb2 = document.createElement("span");
	dlb2.className = "action-button-text";
	dlb2.textContent = "Download Video";
	dlb2.setAttribute("style", "vertical-align:baseline!important;");
	URLDLbox.appendChild(dlb2);
	dlb3 = document.createElement("span");
	dlb3.className = "action-button-rightcap";
	dlb3.setAttribute("style", "vertical-align:baseline!important;");
	URLDLbox.appendChild(dlb3);
		document.getElementById("search-form").parentNode.insertBefore(URLDLbox,document.getElementById("search-form"));
}

function runIt(a1) {
	a2 = a1.length; a1 = a1[a2-1].textContent.toString();
	a1 = a1.split("var fullscreenUrl =")[1];
	a2 = a1.split("&video_id=")[1].split("&")[0];
	a3 = a1.split("&sk=")[1].split("&")[0];
	a4 = a1.split("&t=")[1].split("&")[0];
	aLink = 'http://www.youtube.com/get_video?fmt=18&video_id=' + a2 + '&t=' + a4;
	addBox(aLink);
}

if (scrhead!=null&&scrhead!="") {
	runIt(scrhead);
}