Javascript/タイピングゲーム

var text = document.getElementById("text");
var error = document.getElementById("error");
var count = document.getElementById("count");
var pic = document.getElementById("pic");
var textLists = [
	"kinmokusei",
	"aberia",
	"tubaki",
	"kanamemoti",
	"yamaboushi",
	"metasekoia"
];
var picLists = [
	"img/kinmokusei.jpg",
	"img/aberia.jpg",
	"img/tubaki.jpg",
	"img/kanamemoti.jpg",
	"img/yamaboushi.jpg",
	"img/metasekoia.jpg"
];
var checkTexts = [];
var rnd;
var num = 1;

function createText(){
  rnd = Math.floor(Math.random()*textLists.length);
  if(num > 5){
  	text.textContent = "終了";
  	text.style.fontSize = "15px";
  	return false;
  } else {
    text.textContent = "";
  }
  checkTexts = textLists[rnd].split("").map(function(value){ 
    var span = document.createElement("span");
    span.textContent = value;
    text.appendChild(span);
    return span;
  });
  pic.src = picLists[rnd];
  count.innerText = num + "/5";
}

document.addEventListener("keydown", keyDown);

function keyDown(e){
  if(e.key === checkTexts[0].textContent){
  	checkTexts[0].className = "add-blue";
  	checkTexts.shift();
  	if(!checkTexts.length){
  		textLists.splice(rnd, 1);
  		picLists.splice(rnd, 1);
  		num++;
  		createText();
  	}
  } else {
  	error.innerText = "押したのは" + e.key + "だよ";
  }
}

var startTime = new Date();
var time = document.getElementById("time");
var timer;
var startBtn = document.getElementById("startBtn");

function timeFunc(){
  timer = setTimeout(function(){
    var t = new Date() - startTime;
    time.innerHTML = (t/1000).toFixed(2);
    timeFunc();
  },10);
  startBtn.style.display = "none";
  if(num > 5){
  	clearTimeout(timer);
  	error.textContent = "";
  	time.style.fontSize = "25px";
  	time.innerText += "秒";
  }
}

startBtn.addEventListener("click", createText);
startBtn.addEventListener("click", timeFunc);