var userAgent = navigator.userAgent;
var appName = navigator.appName;

var ms = (appName.indexOf('Micr') != -1);
var mac = (userAgent.indexOf('Mac') != -1 || userAgent.indexOf('mac') != -1);

if (!mac) {
if (ms) document.write('<link rel="stylesheet" type="text/css" charset="Shift_JIS" href="./fontproperty_winie.css">');
else document.write('<link rel="stylesheet" type="text/css" charset="Shift_JIS" href="./fontproperty_winnn.css">');
} 

else {
if (ms) document.write('<link rel="stylesheet" type="text/css" charset="Shift_JIS" href="./fontproperty_macie.css">');
else document.write('<link rel="stylesheet" type="text/css" charset="Shift_JIS" href="./fontproperty_macnn.css">');
}