function iPhoneOS() {
    var version = navigator.userAgent.match('iPod') || navigator.userAgent.match('iPhone') ? 1.0 : false;
    if (match = /iPhone OS (.*) like Mac OS X/.exec(navigator.userAgent)) {
        version = parseInt(match[1].replace('_', ''), 10) / 100;
        if (version < 1) {
            version *= 10;
        }
    }

    return version;
}