Disallowed Raw HTML Extension
(Note: this extension is included by default within the GFM extension)
DisallowedRawHtmlExtension automatically filters certain HTML tags when rendering output, such as:
Filtering is done by replacing the leading
< with the entity
This is required by the GFM spec because these particular tags could cause undesirable side-effects if a malicious user tries to introduce them.
All other HTML tags are left untouched by this extension.
This extension is bundled with
league/commonmark. This library can be installed via Composer:
composer require league/commonmark
See the installation section for more details.
Environment as usual and simply add the
DisallowedRawHtmlExtension provided by this package:
use League\CommonMark\CommonMarkConverter; use League\CommonMark\Environment; use League\CommonMark\Extension\DisallowedRawHtml\DisallowedRawHtmlExtension; // Obtain a pre-configured Environment with all the CommonMark parsers/renderers ready-to-go $environment = Environment::createCommonMarkEnvironment(); // Add this extension $environment->addExtension(new DisallowedRawHtmlExtension()); // Instantiate the converter engine and start converting some Markdown! $converter = new CommonMarkConverter(, $environment); echo $converter->convertToHtml('I cannot change the page <title>anymore</title>');