function detectMacXFF() {
  var userAgent = navigator.userAgent.toLowerCase();
  if (userAgent.indexOf('mac') != -1 && userAgent.indexOf('firefox')!=-1) {
    return true;
  }
}
function detectMacXSafari() {
  var userAgent = navigator.userAgent.toLowerCase();
/*  if ( userAgent.indexOf('mac') != -1 &&  userAgent.indexOf('safari')!=-1) {*/
  if (userAgent.indexOf('safari')!=-1) {
    return true;
  }
}