var CssDir ='/css/';
var CssType = 'other.css';
ua = navigator.userAgent;
if (ua.match(/Win(dows )?NT 6/)) {// Windows7の処理
	os = "Windows 7";
	CssType = 'vista.css';
}

else if (ua.match(/Win(dows )?(NT 5\.1|XP)/)) {// Windows XPの処理
	os = "Windows XP";
}
document.write('<link rel="stylesheet" type="text/css" href="'+CssDir  + CssType + '" />');