<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">

    <title>猜数字游戏</title>

    <style>
      html {
        font-family: sans-serif;
      }

      body {
        width: 50%;
        max-width: 800px;
        min-width: 480px;
        margin: 0 auto;
      }

      .lastResult {
        color: white;
        padding: 3px;
      }
    </style>
  </head>

  <body>
    <h1>猜数字游戏</h1>

    <p>我刚才随机选定了一个100以内的自然数。看你能否在 10 次以内猜中它。每次我都会告诉你所猜的结果是高了还是低了。</p>

    <div class="form">
      <label for="guessField">请猜数：</label><input type="text" id="guessField" class="guessField">
      <input type="submit" value="我猜" class="guessSubmit">
    </div>

    <div class="resultParas">
      <p class="guesses"></p>
      <p class="lastResult"></p>
      <p class="lowOrHi"></p>
    </div>

    <script>
      let randomNumber = Math.floor(Math.random() * 100) + 1;
      const guesses = document.querySelector('.guesses');
      const lastResult = document.querySelector('.lastResult');
      const lowOrHi = document.querySelector('.lowOrHi');
      const guessSubmit = document.querySelector('.guessSubmit');
      const guessField = document.querySelector('.guessField');
      let guessCount = 1;
      let resetButton;

      function checkGuess() {
        let userGuess = Number(guessField.value);
        if (guessCount === 1) {
          guesses.textContent = '上次猜的数：';
        }

        guesses.textContent += userGuess + ' ';

        if (userGuess === randomNumber) {
          lastResult.textContent = '恭喜你！猜对了！';
          lastResult.style.backgroundColor = 'green';
          lowOrHi.textContent = '';
          setGameOver();
        } else if (guessCount === 10) {
          lastResult.textContent = '!!!游戏结束!!!';
          lowOrHi.textContent = '';
          setGameOver();
        } else {
          lastResult.textContent = '你猜错了！';
          lastResult.style.backgroundColor = 'red';
          if(userGuess < randomNumber) {
            lowOrHi.textContent = '你刚才猜低了！' ;
          } else if(userGuess > randomNumber) {
            lowOrHi.textContent = '你刚才猜高了！';
          }
        }

        guessCount++;
        guessField.value = '';
        guessField.focus();
      }

      guessSubmit.addEventListener('click', checkGuess);

      function setGameOver() {
        guessField.disabled = true;
        guessSubmit.disabled = true;
        resetButton = document.createElement('button');
        resetButton.textContent = '开始新游戏';
        document.body.appendChild(resetButton);
        resetButton.addEventListener('click', resetGame);
      }

      function resetGame() {
        guessCount = 1;
        const resetParas = document.querySelectorAll('.resultParas p');
        for(let i = 0 ; i < resetParas.length ; i++) {
          resetParas[i].textContent = '';
        }

        resetButton.parentNode.removeChild(resetButton);
        guessField.disabled = false;
        guessSubmit.disabled = false;
        guessField.value = '';
        guessField.focus();
        lastResult.style.backgroundColor = 'white';
        randomNumber = Math.floor(Math.random() * 100) + 1;
      }
    </script>
  </body>
</html>
