document.addEventListener('DOMContentLoaded', function () {
    const loanAmount = document.getElementById('loanAmount');
    const interestRate = document.getElementById('interestRate');
    const loanTerm = document.getElementById('loanTerm');
    const monthlyPayment = document.getElementById('monthlyPayment');

    function calculatePayment() {
        const p = parseFloat(loanAmount.value);
        const r = parseFloat(interestRate.value) / 100 / 12;
        const n = parseFloat(loanTerm.value) * 12;

        if (p > 0 && r > 0 && n > 0) {
            const monthly = (p * r * Math.pow(1 + r, n)) / (Math.pow(1 + r, n) - 1);
            monthlyPayment.textContent = '$' + monthly.toFixed(2);
        } else {
            monthlyPayment.textContent = '$0.00';
        }
    }

    loanAmount.addEventListener('input', calculatePayment);
    interestRate.addEventListener('input', calculatePayment);
    loanTerm.addEventListener('input', calculatePayment);
});