isPrimeDriill.js

function isPrime(num){
  if(num % 2 == 0 && num != 2) return false;
  for(var i = 3; i * i <= num; i += 2){
    if(num % i == 0) return false;
  }
  return true;
}
// ↑素数かどうかを判定する関数はたったの7行です。ね、簡単でしょう？

function primeFactorizationNotation(num){
  var ret = "";
  if(num % 2 == 0){
    var count = 0;
    while(num % 2 == 0){
      num /= 2;
      count++;
    }
    ret += 2;
    if(count != 1){
      ret += " ^ " + count;
    }
  }
  for(var i = 3; i <= num; i += 2){
    if(num % i == 0){
      var count = 0;
      while(num % i == 0){
        num /= i;
        count++;
      }
      if(ret != ""){
        ret += " x ";
      }
      if(count == 1){
        ret += i;
      }else{
        ret += i + " ^ " + count;
      }
      i = 3;
    }
  }
  return ret;
}

var targetNum; // 判定対象の数
var countTotal = 0; // 回答数
var count_corret = 0; // 正答数
function onButtonClick_Judge(event, isYes){
  event.preventDefault();

  var isCorrect = isYes == isPrime(targetNum);
  var result = (isCorrect ? '○' : '×') + ': ';
  count_corret += isCorrect ? 1 : 0;
  countTotal++;
  if(isCorrect == isYes){
    result += targetNum + " is a prime number.\n";
  }else{
    result += targetNum + " = " + primeFactorizationNotation(targetNum) + "\n";
  }
  updateNum();
  updateResult(result);
}

var spanTargetNum;
var textareaResults;
var spanResults;
function updateResult(result){
  textareaResults.value = result + textareaResults.value;
  spanResults.innerHTML = "正答数/回答数 = " + count_corret + "/" + countTotal + " = " + (Math.round((100 * count_corret / countTotal) * 100) / 100) + "%";
}

var last = [1, 3, 7, 9, 11, 13];
function updateNum(){
  var rand1 = Math.floor(Math.random() * 13) + 1;
  var rand2 = Math.floor(Math.random() * 14);
  var rand3 = last[Math.floor(Math.random() * 6)];
  targetNum = Number(String(rand1) + String(rand2) + String(rand3));
  updateText();
}

function updateText(){
  spanTargetNum.innerHTML = "「" + targetNum + "」は、<br>";
}

window.addEventListener('load', function(){
  spanTargetNum = document.getElementById('spanTargetNum');
  textareaResults = document.getElementById("textareaResults");
  textareaResults.value = "";
  spanResults = document.getElementById("spanResults");
  targetNum = 1213;
  updateText();
});