var browserName=navigator.appName; 
var browserVer=parseInt(navigator.appVersion); 
if (browserName=="Microsoft Internet Explorer" && browserVer<=6) 
  version="n3"; 
else 
  version="n2"; 

if (version=="n3")
	document.write( "<link rel=stylesheet type=text/css href=includes/css/ie.css>");
else
	document.write( "<link rel=stylesheet type=text/css href=includes/css/other.css>");