function display_search_field($value=0) {
        $selectors = html_writer::select_time('days', 'f_'.$this->field->id.'_d', $value['timestamp'])
           . html_writer::select_time('months', 'f_'.$this->field->id.'_m', $value['timestamp'])
           . html_writer::select_time('years', 'f_'.$this->field->id.'_y', $value['timestamp']);
        $datecheck = html_writer::checkbox('f_'.$this->field->id.'_z', 1, $value['usedate']);
        $str = '<div class="form-inline">' . $selectors . ' ' . $datecheck . ' ' . get_string('usedate', 'data') . '</div>';

        return $str;
    }