function CountDown() { var count = 3; var tmID; var infobox = document.getElementById("info"); var start = document.getElementById("start"); var clear = document.getElementById("clear"); function countDown() { if (--count < 0) { infobox.innerHTML = "失敗"; } else { infobox.innerHTML = count + "秒前"; tmID = setTimeout(countDown, 1000); } } function startCountDown() { tmID = setTimeout(countDown, 1000); var list = document.getElementsByTagName('div'); for (let i of list){ i.removeEventListener("click", startCountDown, false); clear.addEventListener('click', stopCountDown); } } function stopCountDown() { if (count >= 0) { clearTimeout(tmID); infobox.innerHTML = "成功"; } } start.addEventListener("click", startCountDown, false); }; document.addEventListener("DOMContentLoaded", CountDown, false);