AJAX Submission of Mailchimp Form with Internationalization; Uses jQuery

newsletter.js

var SUCCESS_MESSAGES = {
  'en': {
    'complete the subscription': 'Confirm the subscription in your inbox',
    'default': 'Confirm the subscription in your inbox'
  },
  'de': {
    'complete the subscription': 'Bestätigen Sie das Abonnement in Ihrer Inbox',
    'default': 'Bestätigen Sie das Abonnement in Ihrer Inbox'
  }
}

var ERROR_MESSAGES = {
  'en': {
    'contain a single': 'Your email must contain an @',
    'enter a value': 'Your email can\'t be blank',
    'the portion after': 'Your email looks incorrect',
    'the portion before': 'Your email looks incorrect',
    'looks fake or invalid': 'Your email looks incorrect',
    'already subscribed': 'Your email is already subscribed',
    'default': 'Your subscription didn\'t go through. Try again.'
  },
  'de': {
    'contain a single': 'Ihre E-Mail muss eine @',
    'enter a value': 'Ihre E-Mail kann nicht leer sein',
    'the portion after': 'Ihre E-Mail-Adresse ist falsch',
    'the portion before': 'Ihre E-Mail-Adresse ist falsch',
    'looks fake or invalid': 'Ihre E-Mail-Adresse ist falsch',
    'already subscribed': 'Ihre E-Mail ist schon abonniert',
    'default': 'Ihr Abonnement ging nicht durch. Versuch es noch einmal.'
  }
};

function getMessage(target, where) {
  for (var piece in where) {
    if(target.indexOf(piece) >= 0) {
      return where[piece];
    }
  }

  return where['default'];
}

// return an appropriate success message
function getSuccessMessage(message, lang) {
  return getMessage(message, SUCCESS_MESSAGES[lang]);
}

// return an appropriate error message
function getErrorMessage(message, lang) {
  return getMessage(message, ERROR_MESSAGES[lang]);
}

function handleSubmitSuccess($form, data, message, xhr) {
  var $message = $form.find('.message');
  var $input = $form.find('input[type="email"]');
  var lang = $form.hasClass('de') ? 'de' : 'en';

  if(data.result === 'error') {
    $form.addClass('error');
    $message.text(getErrorMessage(data.msg, lang));
    $input.focus();
    return;
  }

  $form.addClass('ok');
  $message.text(getSuccessMessage(data.msg, lang));
  $input.blur();
  $form.focus();
}

function handleSubmitError($form) {
  var $message = $form.find('.message');
  var $input = $form.find('input[type="email"]');
  var lang = $form.hasClass('de') ? 'de' : 'en';

  console.error('Submit error', arguments)

  $form.addClass('error');
  $message.text(getErrorMessage('default', lang));
  $input.focus();
}

function handleSubmitTeardown($form) {
  var $submit = $form.find('input[type="submit"]');
  $submit.prop('disabled', false);
}

function handleSubmit(event) {
  var $form = $(event.target).closest('form');
  var $submit = $form.find('input[type="submit"]');
  var $input = $form.find('input[type="email"]');
  var url = $form.attr('action');
  var requestData = {};

  event.preventDefault();

  $.each($form.serializeArray(), function (index, item) {
    requestData[item.name] = item.value;
  });

  $submit.prop('disabled', true);
  $form.removeClass('ok error');

  $.ajax({
    url: url,
    data: requestData,
    dataType: 'jsonp'
  })
  .done($.proxy(handleSubmitSuccess, this, $form))
  .fail($.proxy(handleSubmitError, this, $form))
  .always($.proxy(handleSubmitTeardown, this, $form));
  $input.focus();
}

function handleFocus(event) {
  var $target = $(event.target);
  var $form = $target.closest('form');

  if($form.hasClass('ok')) {
    $form.removeClass('ok');
  }
}

function init() {
  var $form = $('.newsletter form');
  var $input = $('.newsletter input[type="email"]');

  $form.on('submit', handleSubmit);
  $input.on('focus', handleFocus);
}

$(init);