function CountDown() {
    var count = 4, tmID, infobox = document.getElementById("start"), fin = document.getElementById("fin"), are = document.querySelectorAll("div"),clickbutton;
    function countDown() {
	if (--count == 0) {
	    infobox.innerHTML = "時間切れ";
	    //num = Math.floor(Math.ramdom()*10+1);
	    clickbutton.removeEventListener("click", stopCountDown, false);
	} else {
	    fin.innerHTML = count + "秒前";
	    tmID = setTimeout(countDown, 1000);
	}
    }
    function startCountDown() {
	tmID = setTimeout(countDown, 1000);
	infobox.removeEventListener("click", startCountDown, false);
	clickbutton.addEventListener("click", stopCountDown, false);
    }
    function stopCountDown() {
    	num = Math.floor(Math.ramdom()*10+1);
	if (count >= 0){
	    clearTimeout(tmID);
	    infobox.innerHTML = "成功";
	}
	fin.innerHTML = "終了";
	are[num].innerHTML = "正解";
	are[num].removeEventListener("click", stopCountDown, false);
    }
    infobox.addEventListener("click", startCountDown, false);
};
document.addEventListener("DOMContentLoaded", CountDown, false);