function getBestQuality(videoID) {

		xhr=new XMLHttpRequest();
		var param_array = new Array('&el=detailpage');
		var txtDoc = "";
		for(var i = 0; i < param_array.length; ++i)
		{
			var param = param_array[i];

			var send_to_url = 'http://www.youtube.com/get_video_info?&video_id=' + videoID + param + '&ps=default&eurl=&gl=US&hl=en';
			xhr.open("GET", send_to_url, false);
			xhr.setRequestHeader("Accept-Encoding", "identity");
			xhr.setRequestHeader("Accept-Language", "en-us,en;q=0.5");
			xhr.setRequestHeader("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
			xhr.setRequestHeader("User-Agent", "Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.6) Gecko/20100627 Firefox/3.6.6");
			xhr.setRequestHeader("Accept-Charset", "ISO-8859-1,utf-8;q=0.7,*;q=0.7");
			xhr.setRequestHeader("Connection", "close");

			xhr.send();

			txtDoc=xhr.responseText;
			if(txtDoc.indexOf('fmt_url_map'))
			{
				break;
			}

			if(txtDoc.indexOf('url_encoded_fmt_stream_map'))
			{
				break;
			}
		}

		xhr.destroy();

		var paare = txtDoc.split("&");

		var paar, name, wert;
		var params=new Array();
		for (var i = 0; i < paare.length; i++)
                                       {
			paar = paare[i].split("=");
			name = paar[0];
			wert = paar[1];
			params[name] = unescape(wert);
		}
		var url ="";

		if(params['fmt_url_map'])
		{

			var test = params['fmt_url_map'].split(",");

			for (var index = 0; index < test.length; index++)
			{
				var videoinfo = test[index].split("|");

				if (videoinfo[0] == '22')
				{
					url = videoinfo[1];
					alert(videoinfo[0]);
					alert("HD 720p");
					break;
				}
			}
		}

      url = params['url_encoded_fmt_stream_map'].replace("url=","");
      url = parser(url, '&url=', ',itag');
      url = url.replace("&sig", "&signature");

		if(params['url_encoded_fmt_stream_map'])
		{

			var test = params['url_encoded_fmt_stream_map'].split(",url=");

			for (var index = 0; index < test.length; index++)
			{

				var need_help = test[index].indexOf(',itag');
				if(need_help>0)
				{
					var helper = test[index].substr(0,need_help);
					alert('helper' + helper)
					test[index] = helper
				}

				var videoinfo = test[index].split("&itag=");
				videoinfo[0] = videoinfo[0].replace("url=","");

				if (videoinfo[1] == '22')
				{
					url = videoinfo[0];
					mode = "HD 720p"
					break;
				}
				if (videoinfo[1] == '18')
				{
					url = videoinfo[0];
					break;
				}
				if (videoinfo[1] == '5')
				{
					url = videoinfo[0];
					break;
				}
			}
		}


		url = url.replace(/\%3A/g,":");
		url = url.replace(/\%2F/g,"/");
		url = url.replace(/\%3F/g,"?");
		url = url.replace(/\%3D/g,"=");
		url = url.replace(/\%252C/g,",");
		url = url.replace(/\%26/g,"&");
		url = url.replace(/\%253/g,":");

		return url;
}