Question

我已决定创建一个小型应用，如果用户正确回答，它会随机为您提供2个数字和一个符号（-或+），它应该console.log('hey');并显示新的2个数字和一个符号。现在，我的应用仅显示两个数字，即使用户回答正确，也总是说console.log('foo');。这很简单，但我不明白为什么我可能会丢失某些东西或忘记了，请帮忙！

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Thinking...</title>
</head>
<body>
    <div>
        <span id="a">A</span> <span id="sign"></span> <span id="b">B</span> =
        <label for="result"></label><input type="number" id="result"> <button type="button" id="btn" onclick="checkResult()">press</button>
    </div>

    <script>
        let numberA = document.getElementById('a'),
            numberB = document.getElementById('b'),
            sign = document.getElementById('sign'),
            input = document.getElementById('result');

        function checkResult(a, b, sign, result) {

            if (sign === '-') {
                return a - b;
            } else if (sign === '+') {
                return a + b;
            }

            if (result === a-b || result === a+b) {
                console.log('hey');
            } else if (result !== a-b || result !== a+b) {
                console.log('foo');
            }

        }

        function getRandomSign() {
            let signs = ['-', '+'];
            return signs[Math.floor(Math.random()*signs.length)];
        }

        function getRandomNumber(a, b) {
            return Math.floor(Math.random() * (b - a + 1)) + a;
        }

        let aRandom = numberA.innerHTML = getRandomNumber(1, 10);
        let bRandom = numberB.innerHTML = getRandomNumber(1, 10);
        let signRandom = sign.innerHTML = getRandomSign();

        console.log(checkResult(aRandom, bRandom, signRandom, input.value));

    </script>
</body>
</html>

Answer 1

var numberA = document.getElementById('a'),
    numberB = document.getElementById('b'),
    sign = document.getElementById('sign'),
    input = document.getElementById('result');
    
var aRandom = numberA.innerHTML = getRandomNumber(1, 10);
var bRandom = numberB.innerHTML = getRandomNumber(1, 10);
var signRandom = sign.innerHTML = getRandomSign();

function checkResult() {
    let temp;
    if (signRandom === '-') {
        temp = aRandom - bRandom;
    } else if (signRandom === '+') {
        temp = aRandom + bRandom;
    }
    if (temp === parseInt(input.value)) {
        console.log('hey');
    } else {
        console.log('foo');
    }

}

function getRandomSign() {
    let signs = ['-', '+'];
    return signs[Math.floor(Math.random()*signs.length)];
}

function getRandomNumber(a, b) {
    return Math.floor(Math.random() * (b - a + 1)) + a;
}

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Thinking...</title>
</head>
<body>
    <div>
        <span id="a">A</span> <span id="sign"></span> <span id="b">B</span> =
        <label for="result"></label><input type="number" id="result"> <button type="button" id="btn" onclick="checkResult()">press</button>
    </div>
</body>
</html>

为什么总是返回“ foo”？

1 个答案: