function css_check(pfad)
{
//css - check
var os ='win'
var browser='ie';
var browserinfo=navigator.userAgent.toLowerCase();

//ermittlung der plattform
if(browserinfo.indexOf("win")!= -1)
	os='win';

	
	
//ermittlung des browsers
if(browserinfo.indexOf("msie")!=-1)
	browser='ie';
else if(browserinfo.indexOf("netscape") != -1)
	browser='ns'
else if(browserinfo.indexOf("mozilla") != -1)
	browser='ns'	
else if(browserinfo.indexOf("netscape6") != -1)
	browser='ns'
else if(browserinfo.indexOf("gecko") != -1)
	browser='ns'
else if(browserinfo.indexOf("netscape7") != -1)
	browser='ns'
	
if(browser=='ns')
{
	version = navigator.appVersion;
	if(version < '5')
		{
			alert("Sorry, but your browser is to old. You need Netscape 6 or higher to show this site correctly");
		}
}

if(browserinfo.indexOf("mac")!=-1)
	os='mac';


	
//style sheet laden
document.write("<link rel='stylesheet' type='text/css' href='" + pfad + os + "_" + browser + ".css'>");
}