window.onload = function () {
    var countdown = 5;
    setInterval(function () {
        if (countdown >= 0) {
            document.getElementById(‘settime‘).innerHTML = countdown;
            countdown--;
        } else {
            clearInterval();
            window.location.href = http://www.mamicode.com/document.getElementById(‘jumpUrl‘).getAttribute(‘href‘);
        }
    }, 1000)
}

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