protected function _listeAddLevel($type = 'ul', $style = '', $img = null, $start = null)
    {
        // get the url of the image, if we want to use a image
        if ($img) {
            if (preg_match('/^url\(([^)]+)\)$/isU', trim($img), $match)) {
                $img = $match[1];
            } else {
                $img = null;
            }
        } else {
            $img = null;
        }

        // prepare the datas
        if (!in_array($type, array('ul', 'ol'))) {
            $type = 'ul';
        }
        if (!in_array($style, array('lower-alpha', 'upper-alpha', 'upper-roman', 'lower-roman', 'decimal', 'square', 'circle', 'disc', 'none'))) {
            $style = '';
        }

        if (!$style) {
            if ($type === 'ul') {
                $style = 'disc';
            } else {
                $style = 'decimal';
            }
        }

        if (is_null($start) || (int) $start<1) {
            $start=0;
        } else {
            $start--;
        }

        // add the new level
        $this->_defList[count($this->_defList)] = array('style' => $style, 'nb' => $start, 'img' => $img);
    }