function toggle_password_visibility() {
  if ($('#password').attr('type') === 'password')
    $('#password').attr('type', 'text');
  else 
    $('#password').attr('type', 'password');
}

function delayed(callback) {
  callback();

  setTimeout(callback, 3000);
}

function show_hide() {
  for (var i = 0; i < arguments.length; i++) {
    var element = arguments[i];

    delayed(function () {
      $(element).toggle();
    });
  }
}

function scrolled_down(offset) {
  return $(window).scrollTop() >= $(document).height() - $(window).height() - offset;
}