browser_version= parseInt(navigator.appVersion);
browser_type = navigator.appName;

if (browser_type == "Microsoft Internet Explorer" && (browser_version >= 4))
 {
 	document.write('<link rel=stylesheet type="text/css" href="stylesheets/ie.css">');
 }
  else if (browser_type == "Netscape" && (browser_version >= 4))
	{
		document.write('<link rel=stylesheet type="text/css" href="stylesheets/netscape.css">');
	}