code: function(options) {
          var mode = options.mode;
          var name = options.name;
          if (mode === 'multiple' && name.slice(-2) !== '[]') {
              name += '[]';
          }
          return (
              '<select name="' + name + '"' + (mode === 'multiple' ? ' multiple' : '') + '></select>'
          );
      }
docs: Renders select-box inside single-select input that was initialized on
  traditional <select> element.
  
  @param options Options object containing the following properties:
  name - Name of the <select> element.
  mode - Mode in which select exists, single or multiple.