Javascript猜谜游戏，定义onkeyup变量

Question

javascript 超级新手。我正在尝试制作一个通灵猜谜游戏。除了 onkeyup 函数，这里的一切都有效。当我打开控制台日志并输入字母时，它告诉我 userGuess 变量未定义。如何定义 userGuess 变量以匹配 onkeyup 函数？

感谢：

    //Available choices
var letterChoices = ['a', 'b', 'c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z']

//score
var wins = 0;
var losses = 0;
var guesses = 9;
var guessesLeft = 9;
var guessedLetters = [];
var letterToGuess = null;

//computer randomly chooses a letter

var computerGuess = letterChoices [Math.floor(Math.random()*letterChoices.length)];

//guesses left function

var updateGuessesLeft = function() {
    document.querySelector('#guessLeft').innerHTML = "Guesses Left: " + guessesLeft;
};

//letter to guess function

var updateletterToGuess = function(){
    this.letterToGuess = this.letterChoices[Math.floor(Math.random() * this.letterChoices.length)];
};

var updateGuessesSoFar = function(){
    document.querySelector('#let').innerHTML = "Your guesses so far: " + guessedLetters.join(', ');
};

//reset

var reset = function(){
    totalGuesses = 9;
    guessesLeft = 9;
    guessedLetters = [];

    updateletterToGuess();
    updateGuessesSoFar();
    updateGuessesLeft();

};

updateGuessesLeft();
updateletterToGuess();

//user input key

document.onkeyup = function(event) {
    guessesLeft--;
    var userGuess;
    console.log(userGuess)

    guessedLetters.push(userGuess);
    updateGuessesLeft();
    updateGuessesSoFar();

        if (guessesLeft > 0){
            if (userGuess === letterToGuess){
                wins++;
                document.querySelector('#wins').innerHTML = 'Wins: ' + wins;
                alert("How did you know!?!");
                reset();
            }
        } else if (guessesLeft == 0){
            losses++;
            document.querySelector('#losses').innerHTML = 'Losses: ' + losses;
            alert("Sorry, you're not a psychic!");

            reset();
        }
}

Answer 1

变量userGuess是undefined因为它刚刚被声明。这个变量没有发生赋值操作。我查看了工作示例，在浏览器中对其进行了修改，它似乎按预期工作。我做的唯一改变是 assign userGuess 到按下的键，如下

var userGuess = event.key;

这是我对您的代码进行一些尝试后得到的输出

既然你有一个你想要允许的字符列表，你可以在开头添加以下代码，以确保不考虑允许字符以外的任何字符

if (letterChoices.indexOf(userGuess) === -1) return;

Javascript猜谜游戏，定义onkeyup变量

Javascript guessing game, defining onkeyup variable

javascript

function

onkeyup