Filtering the Comment Form Allowed Tags

Question

How can I remove some of the allowed HTML tags in comments/posts? For whatever reason, the following code, placed in my theme's functions.php, didn't work:

add_action('init', 'my_html_tags_code', 10);
function my_html_tags_code() {
    define('CUSTOM_TAGS', true);
    global $allowedposttags, $allowedtags;
    $allowedposttags = array(
        'strong' => array(),
        'em' => array(),
        'pre' => array(),
        'code' => array(),
        'a' => array(
          'href' => array (),
          'title' => array ())
    );

    $allowedtags = array(
        'strong' => array(),
        'em' => array(),
        'a' => array(
          'href' => array (),
          'title' => array ())
    );
}

Tags such as <div> or <pre> are still available when commenting.

Answer 1

There's a filter-hook that allows you to run some checking before comment is posted so you could use it too :

add_filter('preprocess_comment', 'wpse_158147_check_new_comment');
function wpse_158147_check_new_comment($commentdata){

    $commentdata['comment_content'] = preg_replace("/<tag(.*?)>(.*)<\/tag>/", "$2", $commentdata['comment_content']);// or str_replace
    return $commentdata;

}

Here "tag" would be stripped (to be replaced here with your specific tag).

Answer 2

Try hooking to a later hook for comment tags.

function my_comment_tags() {
    global $allowedtags;
    $allowedtags = array(
        'strong' => array(),
        'em' => array(),
        'a' => array(
          'href' => array (),
          'title' => array ())
    );
}

add_action('comment_post', 'my_comment_tags');

Answer 3

This code has them all removed. Simply add back what you want to return in the code which goes in your functions file

add_filter( 'comment_form_defaults', 'wpsites_remove_comment_form_allowed_tags' );
function wpsites_remove_comment_form_allowed_tags( $defaults ) {

    $defaults['comment_notes_after'] = '';
    return $defaults;

}