notification-permission.html

<!DOCTYPE html>
<html>
<body>
</body>
<script>
function getNotificationPermission(callback) {
  if ('permissions' in navigator) {
    navigator.permissions.query({name:'notifications'}).then(function(p) {
      callback(p.state);
    });
    return;
  }

  setTimeout(function() {
    var status = Notification.permission;
    if (status == 'default')
      status = 'prompt';
    callback(status);
  }, 0);
}

getNotificationPermission(function(state) {
  var div = document.createElement('div');
  div.innerHTML = state;
  document.body.appendChild(div);
});
</script>
</html>