Question

我是JavaScript的新手，我正在做一个上课的项目。到目前为止，还没有任何问题，直到出现此问题为止，在我输入输入内容时，什么都不会打印。当我输入问题时，根本没有任何变化。这个问题只是应该创建一个随机数，然后查看用户是否正确猜到了。

<script>
function playGame() {
    var answer;
    var x = Math.floor((Math.random() * 100) + 1);
    var name = document.getElementById('name').value;
    var guess = document.getElementById('guess').value;
    if (x > guess) {
    var answer = "Guess is too low!");
    }
    else if (x < guess) {
    var answer = "Guess is too high!");
    }
    else if (x == guess) {
    var answer = "You guessed correctly!");
    }
    document.getElementById('final').innerHTML = "Answer: " + answer;
</script>

<h2>Random Number Game by </h2>
    <p>Enter Name: 
       <input id="name" type="text">
    </p>
    <p>Enter Guess: <input id="guess" type="number" min="1" max="100" onchange="playGame()"></p>
    <h2 id="final"></h2>

Answer 1

代码中存在语法错误。在)语句中删除结尾的右括号if..else。 document.getElementById('final').innerHTML = "Answer: " + answer;应该在函数内。 var answer;只需要在脚本开头声明一次。

在{{1}之外将x定义为undefined，如果playGame则将x设置为undefined并将x == guess设置为{ {1}}。

Answer 2

您的代码有一些问题：

您需要通过使用大括号undefined结束它来关闭函数
在<script> let x; function playGame() { var answer; if (!x) { x = Math.floor((Math.random() * 100) + 1) }; var name = document.getElementById('name').value; var guess = document.getElementById('guess').value; if (x > guess) { answer = "Guess is too low!"; } else if (x < guess) { answer = "Guess is too high!"; } else if (x == guess) { answer = "You guessed correctly!"; x = void 0; } document.getElementById('final').innerHTML = "Answer: " + answer; } </script> <h2>Random Number Game by </h2> <p>Enter Name: <input id="name" type="text"> </p> <p>Enter Guess: <input id="guess" type="number" min="1" max="100" onchange="playGame()"></p> <h2 id="final"></h2>声明的末尾删除}
假设您希望游戏只使用一个随机数，而不希望每次猜测时都保持不变，则可以将)移到answer函数之外。这样var x = Math.floor((Math.random() * 100) + 1);只会设置一次，而不是每次输入新的猜测值
虽然不需要，但不必每次都使用playGame()重新初始化x变量。正如您已经声明的那样，您可以通过引用answer

请参见下面的工作示例：

var

Answer 3

以下内容对我来说似乎是错误的-

if (x > guess) {
    var answer = "Guess is too low!");
}
else if (x < guess) {
    var answer = "Guess is too high!");
}
else if (x == guess) {
    var answer = "You guessed correctly!");
}

为什么在每个语句的末尾有额外的）？您能否尝试在第一个answer之外定义变量if，然后为其赋值？

Answer 4

从代码中纠正了一些错字。
innerHTML语句应位于函数内部。
使用oninput事件代替onchange，因为当从任何源输入任何输入时，它将触发处理程序功能。

function playGame() {
  var answer;
  var x = Math.floor((Math.random() * 100) + 1);
  var name = document.getElementById('name').value;
  var guess = document.getElementById('guess').value;
  if (x > guess) {
    var answer = "Guess is too low!";
  } else if (x < guess) {
    var answer = "Guess is too high!";
  } else if (x == guess) {
    var answer = "You guessed correctly!";
  }
  document.getElementById('final').innerHTML = "Answer: " + answer;
}

<h2>Random Number Game by </h2>
<p>Enter Name:
  <input id="name" type="text">
</p>
<p>Enter Guess: <input id="guess" type="number" min="1" max="100" oninput="playGame()"></p>
<h2 id="final"></h2>

Answer 5

它不起作用的原因是因为您没有该函数的右括号，并且在定义answer的每一行上都有多余的括号：

function playGame() {
    var answer;
    var x = Math.floor((Math.random() * 100) + 1);
    var name = document.getElementById('name').value;
    var guess = document.getElementById('guess').value;
    if (x > guess) {
    var answer = "Guess is too low!";
    }
    else if (x < guess) {
    var answer = "Guess is too high!";
    }
    else if (x == guess) {
    var answer = "You guessed correctly!";
    }
    document.getElementById('final').innerHTML = "Answer: " + answer;
}

<h2>Random Number Game by </h2>
<p>Enter Name: 
   <input id="name" type="text">
</p>
<p>Enter Guess: <input id="guess" type="number" min="1" max="100" onchange="playGame()"></p>
<h2 id="final"></h2>

JavaScript函数无法打印

5 个答案: