drupal/core/modules/locale/locale.admin.js

(function ($) {

"use strict";

/**
 * Markes changes of translations
 */
Drupal.behaviors.localeTranslateDirty = {
  attach: function () {
    var $form = $("#locale-translate-edit-form").once('localetranslatedirty');
    if ($form.length) {
      // Display a notice if any row changed.
      $form.one('change.localeTranslateDirty', 'table', function () {
        var $marker = $(Drupal.theme('localeTranslateChangedWarning')).hide();
        $(this).addClass('changed').before($marker);
        $marker.fadeIn('slow');
      });
      // Highlight changed row.
      $form.on('change.localeTranslateDirty', 'tr', function (e) {
        var
          $row = $(this),
          $rowToMark = $row.once('localemark'),
          marker = Drupal.theme('localeTranslateChangedMarker');

        $row.addClass('changed');
        // Add an asterisk only once if row changed.
        if ($rowToMark.length) {
          $rowToMark.find('td:first-child .form-item').append(marker);
        }
      });
    }
  },
  detach: function (context, settings, trigger) {
    if (trigger === 'unload') {
      var $form = $("#locale-translate-edit-form").removeOnce('localetranslatedirty');
      if ($form.length) {
        $form.off('change.localeTranslateDirty');
      }
    }
  }
};

$.extend(Drupal.theme, {
  localeTranslateChangedMarker: function () {
    return '<abbr class="warning ajax-changed" title="' + Drupal.t('Changed') + '">*</abbr>';
  },
  localeTranslateChangedWarning: function () {
    return '<div class="localetranslate-changed-warning messages warning">' + Drupal.theme('localeTranslateChangedMarker') + ' ' + Drupal.t('Changes made in this table will not be saved until the form is submitted.') + '</div>';
  }
});

})(jQuery);