javascript - 元素内部 html 未清除

Question

我用 JavaScript 创建了一个简单的测验应用程序。

当用户选择一个选项来回答问题并提交时，上一个问题的选项不应该可见。

不幸的是，他们是，我不确定为什么。当我试图在 askQuestion() 函数中将 quizQuestion 分离到它自己的 div 中时，问题发生了。

我在下面包含了代码和 fiddle 。

https://jsfiddle.net/scrippyfingers/z84pc45t/

这是JavaScript

var allQuestions = [
    {
        question: "what time is it?",
        choices: ["10AM", "11AM", "Hammertime"],
        correctAnswer: 2
    },
    {
        question: "what is for lunch?",
        choices: ["Pizza", "Soup", "Tacos"],
        correctAnswer: 0
    },
    {
        question: "what?",
        choices: ["who", "where", "how"],
        correctAnswer: 1
    }
];

var submitBtn = document.getElementById("myBtn");

var currentQuestion = 0;
var tally = 0;

var quizForm = document.getElementById("quiz");
var quizQuestion = document.getElementById("quizQuestion");

var question;
var choices;

var radioButtons = document.getElementsByName('radioOption');

var index = 0;

function beginQuiz(){
    if(currentQuestion === 0){
        submitBtn.value = "Start Quiz";
    }
}

function askQuestion(){
    choices = allQuestions[currentQuestion].choices;
    question = allQuestions[currentQuestion].question;
    if(currentQuestion < allQuestions.length){
        submitBtn.value = "Next";
        quizQuestion.innerHTML = "<p class='quizQuestion'>" + question + "</p>";
        for(var i = 0; i < choices.length; i++){
            quizForm.innerHTML += " <label class='answerChoice'><input type= 'radio' name= 'radioOption' value=' " + choices[i] + "'/>" + choices[i] + "</label>" + "<br>";  
        }
        if(currentQuestion == allQuestions.length - 1){
            submitBtn.value = "Submit";
        } else if(currentQuestion > allQuestions.length - 1){
            calcQuiz();
        }
    }
}

function lookForChecked(){
    if(radioButtons.length > 1){
        var checked = false;
        for(var i = 0; i < radioButtons.length; i++){
            var selection = radioButtons[i];

            if(selection.checked){
                var index = [i];
                if(i === allQuestions[currentQuestion].correctAnswer){
                    tally++;
                }
                if(currentQuestion < allQuestions.length -1){
                    currentQuestion++;
                } else {
                    console.log('you have ended the quiz');
                    calcQuiz();
                    return false;
                }
                break;
            }
        }
        if($('input[name="radioOption"]:checked').length < 1){
            alert('Please Make a Selection');
        }
    }
    askQuestion();
}

function calcQuiz(){
    quizForm.innerHTML = tally + " out of " + allQuestions.length;
    // submitBtn.remove();
    submitBtn.value = "Play again?";
}

window.onload = beginQuiz();
submitBtn.addEventListener('click', lookForChecked);

这是 HTML

<div class="bg1"></div>
  <div id="quizQuestion"></div>
  <div id="quiz"></div>
  <div class="btnContainer">
        <input type='submit' id='myBtn' value='' />
  </div><!-- end div.btnContainer -->

Answer 1

quizForm 永远不会被清除，所以我们只是一直追加它。我在处理该 div 的循环之前添加了这个:quizForm.innerHTML = "";

function askQuestion(){
    choices = allQuestions[currentQuestion].choices;
    question = allQuestions[currentQuestion].question;
    if(currentQuestion < allQuestions.length){
        submitBtn.value = "Next";
        quizQuestion.innerHTML = "<p class='quizQuestion'>" + question + "</p>";
        quizForm.innerHTML = "";
        for(var i = 0; i < choices.length; i++){
            quizForm.innerHTML += " <label class='answerChoice'><input type= 'radio' name= 'radioOption' value=' " + choices[i] + "'/>" + choices[i] + "</label>" + "<br>";  
        }
        if(currentQuestion == allQuestions.length - 1){
            submitBtn.value = "Submit";
        } else if(currentQuestion > allQuestions.length - 1){
            calcQuiz();
        }
    } }