const observer = new MutationObserver(() => { const form = document.querySelector('form[data-cctaid-prepared="true"]'); if (form && !form.querySelector('[name="MERGE5"]')) { const input = document.createElement('input'); input.type = 'hidden'; input.name = 'MERGE5'; // Mailchimp merge field input.value = window.localStorage.getItem('cctaid') || 'not set'; // fallback default form.appendChild(input); console.log('✅ MERGE5 field added with value:', input.value); } }); observer.observe(document.body, { childList: true, subtree: true });