(function($) {

  Drupal.form_placeholder = {};

  Drupal.form_placeholder.placeholderIsSupported = function() {
    // Opera Mini v7 doesn’t support placeholder although its DOM seems to indicate so.
    var isOperaMini = Object.prototype.toString.call(window.operamini) == '[object OperaMini]';
    return 'placeholder' in document.createElement('input') && !isOperaMini;
  };

  Drupal.behaviors.form_placeholder = {
    attach: function(context, settings) {
      var include = settings.form_placeholder.include;
      if (include) {
        include += ', ';
      }
      include += '.form-placeholder-include-children *';
      include += ', .form-placeholder-include';
      var exclude = settings.form_placeholder.exclude;
      if (exclude) {
        exclude += ', ';
      }
      exclude += '.form-placeholder-exclude-children *';
      exclude += ', .form-placeholder-exclude';

      var required_indicator = settings.form_placeholder.required_indicator;

      $(include, context).not(exclude).each(function() {
        $textfield = $(this);

        // Check if element is a textfield.
        if (!$textfield.is('input[type=text], input[type=email], input[type=password], textarea')) {
          return;
        }
        // Placeholder is supported.
        else if (Drupal.form_placeholder.placeholderIsSupported() || settings.form_placeholder.fallback_support) {
          $form = $textfield.closest('form');
          $label = $form.find('label[for=' + this.id + ']');

          if (required_indicator === 'append') {
            $label.find('.form-required').insertAfter($textfield).prepend(' ');
          }
          else if (required_indicator === 'remove') {
            $label.find('.form-required').remove();
          }
          else if (required_indicator === 'text') {
            $label.find('.form-required').text('(' + Drupal.t('required') + ')');
          }

          $textfield.attr('placeholder', $.trim($label.text()));
          $label.hide();

          // Fallback support for older browsers.
          if (!Drupal.form_placeholder.placeholderIsSupported() && settings.form_placeholder.fallback_support) {
            $textfield.placeholder();
          }
        }
      });
    }
  };

})(jQuery);