(() => {
function CountDown() {
    var count = 4, 
    tmID, 
    infobox = document.getElementById("info"), 
    start = document.getElementById("start"),
    kekka = document.getElementById("kekka");
    function countDown() {
	if (--count === 0) {
	    infobox.innerHTML = "ぼかーん!";
	} else {
	    infobox.innerHTML = count + "秒前!";
	    tmID = setTimeout(countDown, 1000);
	}
    }
    function startCountDown() {
	tmID = setTimeout(countDown, 1000);
	infobox.removeEventListener("click", startCountDown, false);
	kekka.addEventListener("click", stopCountDown, false);
    }
    function stopCountDown() {
	clearTimeout(tmID);
	infobox.innerHTML = "停めました!";
	kekka.removeEventListener("click", stopCountDown, false);
    }
    start.addEventListener("click", startCountDown, false);
};
document.addEventListener("DOMContentLoaded", CountDown, false);
})();