PMPro groengraag.nl - Level 5 checkout: single-click submit button + change wording

groengraag-trial-single-submit.php

<?php
/**
 * PMPro - groengraag.nl
 * Levels 5 (Groene Try-Out) & 6 (De groene maand) only: prevent the submit
 * button being clicked more than once, and change its wording while the form
 * submits.
 *
 * Classic [pmpro_checkout] shortcode. Does NOT disable the <input>, so the
 * `submit-checkout` value is still POSTed and checkout completes normally.
 *
 * Add via Code Snippets plugin or a PMPro Customizations include.
 */
function ggraag_checkout_single_submit_trial() {
	if ( ! function_exists( 'pmpro_is_checkout' ) || ! pmpro_is_checkout() ) {
		return;
	}

	// Resolve the level being checked out (handles discount codes / level overrides).
	if ( ! function_exists( 'pmpro_getLevelAtCheckout' ) ) {
		return;
	}
	$target_levels = array( 5, 6 ); // Groene Try-Out, De groene maand.
	$level         = pmpro_getLevelAtCheckout();
	if ( empty( $level->id ) || ! in_array( (int) $level->id, $target_levels, true ) ) {
		return;
	}
	?>
	<script>
	document.addEventListener('DOMContentLoaded', function () {
		var form = document.querySelector('form.pmpro_form, form[name="checkout"], #pmpro_form');
		if (!form) { return; }

		var submitting = false;
		var busyText = 'Even geduld, we maken alles voor je klaar…';

		form.addEventListener('submit', function (e) {
			if (submitting) {
				e.preventDefault(); // Block every click after the first.
				return false;
			}
			submitting = true;

			var btns = form.querySelectorAll(
				'input[name="submit-checkout"], input[type="submit"], button[type="submit"], .pmpro_btn-submit-checkout'
			);
			btns.forEach(function (btn) {
				if (btn.tagName === 'INPUT') { btn.value = busyText; }
				else { btn.textContent = busyText; }
				// Visually disable WITHOUT removing it from the POST.
				btn.style.pointerEvents = 'none';
				btn.style.opacity = '0.6';
				btn.setAttribute('aria-disabled', 'true');
			});
		}, true);
	});
	</script>
	<?php
}
add_action( 'wp_footer', 'ggraag_checkout_single_submit_trial' );