Add Custom Comment Fields

This snippet adds custom fields to the comment form, allowing you to collect additional information from commenters.

PHP

function add_comment_fields($fields) {
    $fields['twitter'] = '<p class="comment-form-twitter"><label for="twitter">' . __('Twitter Username', 'textdomain') . '</label><input id="twitter" name="twitter" type="text" size="30" /></p>';
    return $fields;
}
add_filter('comment_form_default_fields', 'add_comment_fields');

function save_comment_meta($comment_id) {
    if (isset($_POST['twitter'])) {
        $twitter = sanitize_text_field($_POST['twitter']);
        add_comment_meta($comment_id, 'twitter', $twitter);
    }
}
add_action('comment_post', 'save_comment_meta');