var agt=navigator.userAgent.toLowerCase(); 
var nav=navigator.appName.charAt(0); 
var fName; 
if (agt.indexOf("mac")!=-1)  { 
	// mac 
	if(nav=="M") fName = "inc/mac_ie.css"; 
	if(nav=="N") fName = "inc/mac_ns.css"; 
} else {
	if (agt.indexOf("win")!=-1)  { 
// win 
		if(nav=="M") fName = "inc/win_ie.css"; 
		if(nav=="N") fName = "inc/win_ns.css"; 
	} else {
		
	}
}
if (fName != null) { 
		document.write("<LINK REL=STYLESHEET HREF='"+fName+"' TYPE='text/css'>"); 
}