Wordpress add toggle element to mobile menu

/**
 * Add element to open submenus for mobile.
 */
(function($) {
  $(document).ready(function() {
    $('nav.mobile_menu > ul > li.has_sub').each(function() {
      var $submenu = $(this).children('.sub_menu');
      var $link = $(this).children('a');
      var $open = $('<span class="open">&gt;</span>');
      $open.css({
        display: 'inline-block',
        float: 'right',
        height: '26px',
        padding: '10px 0px',
        width: '46px',
        'z-index': '100',
        position: 'absolute',
        right: '0px',
        cursor: 'pointer',
        'text-align': 'center'
      });
      $open.click(function() {
        $submenu.toggle();
      });
      $open.insertBefore($link);
    });
  });
})(jQuery);