var uagent = navigator.userAgent;
		var browser = (uagent.indexOf('Mac')>=0)?"_mac":
		"_win";
		var isIE = (uagent.indexOf('MSIE')>=0)?true:false;
		var isOpera = (uagent.indexOf('Opera')>=0)?true:false;
		var isGecko = (uagent.indexOf('Gecko')>=0)?true:false;
		if(isIE&&!isOpera)
		{cssfile = "ie";}
		else if (isGecko)
		{cssfile = "mozilla";}
		else if (isOpera)
		{cssfile = "opera";}
		else if (document.layers)
		{cssfile = "nn";}
		cssfile +=(browser+'.css');
		document.write('<link rel="stylesheet" type="text/css" href="../css/'+ cssfile +'">');