michelf / php-markdown

				preg_match('{^</?(?:' . $enclosing_tag_re . ')\b}', $tag))

			{

				// Increase/decrease nested tag count.

				if ($tag{1} == '/')						$depth--;

				else if ($tag{strlen($tag)-2} != '/')	$depth++;

				if ($depth < 0) {

					// Going out of parent element. Clean up and break so we

				// Increase/decrease nested tag count. Only do so if

				// the tag's name match base tag's.

				if (preg_match('{^</?' . $base_tag_name_re . '\b}', $tag)) {

					if ($tag{1} == '/')						$depth--;

					else if ($tag{strlen($tag)-2} != '/')	$depth++;

				}

				// Check for `markdown="1"` attribute and handle it.