	an = navigator.appName;	av = navigator.appVersion;	ua = navigator.userAgent;	iev = 4; 	nsv = 4; 	if(ua.indexOf("Win") != -1) //WindowsOS	{		if((an.indexOf("Microsoft") >= 0) && (av.charAt(0) >= iev))		{			document.write("<link rel='stylesheet' href='/css/win/win_ie.css' type='text/css'>"); 		}		else if((an.indexOf("Netscape") >= 0) && (av.charAt(0) >= nsv))		{			document.write("<link rel='stylesheet' href='/css/win/win_ns.css' type='text/css'>"); 		}	}	else if(ua.indexOf("Mac") != -1)//MacOS...	{		if((an.indexOf("Microsoft") >= 0) && (av.charAt(0) >= iev))		{			document.write("<link rel='stylesheet' href='/css/mac/mac_ie.css' type='text/css'>"); 		}		else if((an.indexOf("Netscape") >= 0) && (av.charAt(0) >= nsv))		{			document.write("<link rel='stylesheet' href='/css/mac/mac_ns.css' type='text/css'>"); 		}	}