document.addEventListener("DOMContentLoaded", function () { const amountInput = document.getElementById('amount'); const plans = [ { months: 3, apr: 0, id: 'payment-3' }, { months: 6, apr: 0, id: 'payment-6' }, { months: 12, apr: 15.99, id: 'payment-12' }, { months: 18, apr: 16.99, id: 'payment-18' }, { months: 24, apr: 17.99, id: 'payment-24' } ]; function calculateMonthly(principal, months, apr) { if (apr === 0) return principal / months; const monthlyRate = apr / 100 / 12; return (principal * monthlyRate) / (1 - Math.pow(1 + monthlyRate, -months)); } function updatePayments() { const amount = parseFloat(amountInput.value); if (isNaN(amount) || amount <= 0) { plans.forEach(plan => { const el = document.getElementById(plan.id); if (el) el.textContent = ''; }); return; } plans.forEach(plan => { const el = document.getElementById(plan.id); if (el) { const monthlyPayment = calculateMonthly(amount, plan.months, plan.apr); el.textContent = `Est. Payment: $${monthlyPayment.toFixed(2)}`; } }); } if (amountInput) { amountInput.addEventListener('input', updatePayments); amountInput.addEventListener('blur', updatePayments); } });