Allow only specific days of the month in all WPForms date pickers

/**

 * Allow only specific days of each month in all WPForms date pickers.

 *

 * @link https://wpforms.com/developers/customize-the-date-time-field-date-options/

 */

function wpf_dev_only_selected_days() {

    ?>

    <script type="text/javascript">

        window.wpforms_datepicker = {

            disableMobile: true,

            disable: [

                function(date) {

                    var day = date.getDate();

                    // Disable every day that is NOT the 5th or 20th

                    if (day !== 5 && day !== 20) {

                        return true;  // disabled

                    }

                    return false;    // keep the 5th and 20th enabled

                }

            ]

        };

    </script>

    <?php

}

add_action( 'wpforms_wp_footer_end', 'wpf_dev_only_selected_days', 30 );