Example to change which checkout level is used for modal checkout based on page

pmpro_modal_checkout_custom_level.php

<?php
/**
 * Define the default level to use for the modal
 */
$uri = $_SERVER['REQUEST_URI'];
$page_slug = '/about';
if( strpos($uri, $page_slug) !== false ) {
	define('PMPRO_MODAL_CHECKOUT_DEFAULT_LEVEL', 2);
} else {
	define('PMPRO_MODAL_CHECKOUT_DEFAULT_LEVEL', 1);
}

This recipe is included in the blog post on "Process Membership Checkout in a Modal or Popover Window" at Paid Memberships Pro here: https://www.paidmembershipspro.com/process-membership-checkout-in-a-modal-or-popover-window/