var agt=navigator.userAgent.toLowerCase(); 
var nav=navigator.appName.charAt(0); 
var fName; 
if (agt.indexOf("mac")!=-1) 
{ 
// mac 
if(nav=="M") fName = "styles/fontmac_ie.css"; 
if(nav=="N") fName = "styles/fontmac_ns.css"; 
} else 
if (agt.indexOf("win")!=-1) 
{ 
// win 
if(nav=="M") fName = "styles/fontwin_ie.css"; 
if(nav=="N") fName = "styles/fontwin_ns.css"; 
} else 
{ 
// ?? ‘¼‚̀OS 
fName = "styles/fontwin_ns.css"; 
} 
if (fName != null) { 
document.write("<LINK REL=STYLESHEET HREF='"+fName+"' TYPE='text/css'"); 
}