index.html

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8">
    <meta http-equiv="refresh" content="5; url=./old/index.html" />
    <script>
        window.onload = function () {
            var countDown = 5;
            var countdownElement = document.getElementById('countdown');

            function updateCountdown() {
                countdownElement.textContent = countDown;
                countDown--;
                if (countDown < 0) {
                    clearInterval(interval);
                }
            }

            updateCountdown();
            var interval = setInterval(updateCountdown, 1000);
        };
    </script>
</head>

<body>
    <h1 style="text-align: center;">新版個人網頁即將來臨，敬請期待!</h1>
    <h1 style="text-align: center;">將於<text id="countdown" style="text-align: center;">5</text>秒後跳轉至舊版網頁</h1>
</body>

</html>