tags in code blocks $markdown = preg_replace_callback('/(```.*?```|`[^`]*`)/s', function ($matches) { return str_replace('
', '', $matches[0]); }, $markdown); // Decode HTML entities in inline math and display math $markdown = preg_replace_callback('/(\$\$.*?\$\$|\$[^$]*\$)/s', function ($matches) { return htmlentities($matches[0], ENT_QUOTES, 'UTF-8'); }, $markdown); return $markdown; }