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我试图找出脚本中的错误，并希望有人能够告诉我哪里出错了。它试图创建一个基于 JS/Jquery（javascriptissexy 练习）的测验。

到目前为止它工作正常，除了：我想使用一个后退按钮来调用用户先前给出的答案并相应地设置单选按钮。该脚本不会返回，即使我单击前进，它也不会给我任何错误，可以帮助我查明问题。

再次抱歉，我无法进一步缩小范围，因为我真的不知道哪些部分是相关的/不相关的。如果有人有一些建议如何以更好的方式呈现那些“我几乎要放弃，因为我不知道如何确定问题”的问题，我很乐意这样做。

HTML 单选按钮的结构如下：

 <input type="radio" name="radio" id="Option0" value="Option0" />
 <label for ="Option0">Option0</label>

JS/Jquery：

 $(document).ready(function () {
 var allQuestions = [
    {question: "Who is Prime Minister of the United Kingdom?",
        choices: ["David Cameron", "Gordon Brown", "Winston Churchill", "Tony Blair"],
        correctAnswer: 0},
    {question: "Which color has the sky?",
        choices: ["Grey", "Black", "Blue", "Green"],
        correctAnswer: 2},
    {question: "What's on the chain?",
        choices: ["Monster", "Magician", "Bull", "Skull"],
        correctAnswer: 3}
];

var counter = 0;     // Question No currently processed
var points = 0;        // Total points currently reached by the player
var answers = new Array(); // Array of the choices the player made  eg Q1:0

// Back button in a function
function back() {
    if (counter > 0)          //Checks if there is at least one question already answered
    {
        //Goes back one question

        $("#back").show().on('click', function () {
            counter = counter--;
            quiz();
        });      //Executes quiz loading

    }
    else {
        $("#back").hide();         //If there is no previous question existing the back button is deactivated
    }
}


function qload(counter) {
    $("title").text("Question No ");
    $("#question").text(allQuestions[counter].question);
    back();
    for (var i = 0; i < allQuestions[counter].choices.length; i++) {
        $('label[for=Option' + i + ']').html(allQuestions[counter].choices[i]);

        if (answers["Q" + i]) {
            $("#Option" + i).attr("checked","checked");
        }

        else {
            $("#Option" + i).removeAttr('checked');
        }
    }
};
//this is the result screen giving the final amount of points
function result() {
    $("title").text("Your Results");
    for (var i = 0; i < allQuestions.length; i++) {
        if (allQuestions[i].correctAnswer == answers["Q" + i]) {
            points++;
        }


        $("#result").show().text("CONGRATULATIONS! You answered " + points + " out of " + allQuestions.length + " correct!");
        $(".qbox").hide();
        console.log(answers);

    }
}

function welcome() {
    // this is the welcome screen inviting to start the quizz
    $("title").text("Welcome to the JQuery QuizY");
    $(".qbox").hide();
    $("#result").append().html("Random");
    $("#result").append().html("<p id='start'>Start</p>");
    $("#start").on('click', function () {
        quiz();
    });
}

function quiz() {
    $("#start, #result").hide();
    $(".qbox").show();
    qload(counter);
    $("#next").on('click', function () {
        // this checks that one question is selected before processing
        if ($('#Option0').is(':checked')) {
            answers["Q" + counter] = 0;
            counter++;
        }

        else if ($('#Option1').is(':checked')) {
            answers["Q" + counter] = 1;
            counter++;
        }

        else if ($('#Option2').is(':checked')) {
            answers["Q" + counter] = 2;
            counter++;
        }

        else if ($('#Option3').is(':checked')) {
            answers["Q" + counter] = 3;
            counter++;
        }

        else {
            alert("Please make your selection before continuing!");
        }

        // this checks if there are any questions left, otherwise it goes to the result screen
        if (allQuestions[counter]) {
            qload(counter);
        }
        else {
            result();
        }
    });
}

welcome();

});
4

2 回答 2

3

1) 不能使用字符串作为索引来引用数组元素 (answers["Q" + i])。您必须使用数字作为数组索引，或者使用对象而不是数组。

2) 不要使用 .attr() 方法修改 DOM 属性，例如“checked”。请改用.prop()方法。所以你必须替换这个片段：

if (answers["Q" + i]) {
    $("#Option" + i).attr("checked","checked");
}

else {
    $("#Option" + i).removeAttr('checked');
}

具有以下内容：

$("#Option" + i).prop("checked", Boolean(answers["Q" + i]));

3）您获取用户答案价值的方式非常繁琐但很奇怪。这段代码：

    if ($('#Option0').is(':checked')) {
        answers["Q" + counter] = 0;
        counter++;
    }

    else if ($('#Option1').is(':checked')) {
        answers["Q" + counter] = 1;
        counter++;
    }

    else if ($('#Option2').is(':checked')) {
        answers["Q" + counter] = 2;
        counter++;
    }

    else if ($('#Option3').is(':checked')) {
        answers["Q" + counter] = 3;
        counter++;
    }

    else {
        alert("Please make your selection before continuing!");
    }

可以替换为以下内容：

var oEl = $('input:radio[name=radio]:checked');
if (oEl.length) {
    answers[counter] = parseInt(oEl.val());
    counter++;
}
else {
    alert("Please make your selection before continuing!");
}

还需要对单选按钮的 html 代码进行以下修复：

<input type="radio" name="radio" id="Option0" value="0" />
<label for ="Option0">Option0</label>

加上其他一些变化...

所以总代码更新：

$(document).ready(function () {
var allQuestions = [
    {question: "Who is Prime Minister of the United Kingdom?",
        choices: ["David Cameron", "Gordon Brown", "Winston Churchill", "Tony Blair"],
        correctAnswer: 0},
    {question: "Which color has the sky?",
        choices: ["Grey", "Black", "Blue", "Green"],
        correctAnswer: 2},
    {question: "What's on the chain?",
        choices: ["Monster", "Magician", "Bull", "Skull"],
        correctAnswer: 3}
];

var counter = 0; // Question No. currently processed
var answers = new Array(); // Array of the choices the player made

$('#back').click(function(){
    counter++;
    quiz();
});

// update Back button appearance
function updateBackBtn() {
    if (counter > 0)
        $("#back").show();
    else
        $("#back").hide();
}

// set current question
function qload(counter) {
    $("title").text("Question No ");
    $("#question").text(allQuestions[counter].question);
    updateBackBtn();
    for (var i = 0; i < allQuestions[counter].choices.length; i++) {
        $('label[for=Option' + i + ']').html(allQuestions[counter].choices[i]);

        $("#Option" + i).prop("checked", Boolean(answers[i]));
    }
};

// this is the result screen giving the final amount of points
function result() {
    $("title").text("Your Results");
        var points = 0; // Total points currently reached by the player
    for (var i = 0; i < allQuestions.length; i++) {
        if (allQuestions[i].correctAnswer == answers[i]) {
            points++;
        }
        $("#result").show().text("CONGRATULATIONS! You answered " + points + " out of " + allQuestions.length + " correct!");
        $(".qbox").hide();
        console.log(answers);

    }
}

function welcome() {
    // this is the welcome screen inviting to start the quizz
    $("title").text("Welcome to the JQuery QuizY");
    $(".qbox").hide();
    $("#result").append().html("Random");
    $("#result").append().html("<p id='start'>Start</p>");
    $("#start").on('click', function () {
        quiz();
    });
}

function quiz() {
    $("#start, #result").hide();
    $(".qbox").show();
    qload(counter);
    $("#next").on('click', function () {
        // get an input element containing selected option (answer)
        var oEl = $('input:radio[name=radio]:checked');
        // if such input element exists (any answer selected)
        if (oEl.length) {
            answers[counter] = parseInt(oEl.val());
            counter++;
        }
        else {
            alert("Please make your selection before continuing!");
        }

        // this checks if there are any questions left, otherwise it goes to the result screen
        if (counter < allQuestions.length) {
            qload(counter);
        }
        else {
            result();
        }
    });
}

welcome();

});
于 2013-07-21T15:58:07.363 回答
1

我已经浏览了代码并做了一些改动。

请查看以下更新的代码。

$(document).ready(function () {
                var allQuestions = [
                    {question: "Who is Prime Minister of the United Kingdom?",
                        choices: ["David Cameron", "Gordon Brown", "Winston Churchill", "Tony Blair"],
                        correctAnswer: 0},
                    {question: "Which color has the sky?",
                        choices: ["Grey", "Black", "Blue", "Green"],
                        correctAnswer: 2},
                    {question: "What's on the chain?",
                        choices: ["Monster", "Magician", "Bull", "Skull"],
                        correctAnswer: 3}
                ];

                var counter = 0;     // Question No currently processed
                var points = 0;        // Total points currently reached by the player
                var answers = new Array(); // Array of the choices the player made  eg Q1:0

                // Back button in a function
                function back() {
                    if (counter > 0)          //Checks if there is at least one question already answered
                    {
                        $("#back").show();
                    }
                    else {
                        $("#back").hide();         //If there is no previous question existing the back button is deactivated
                    }
                }

                $('#back').click(function(){
                    counter = --counter;
                    quiz();//Executes quiz loading
                });

                function qload(counter) {
                    $("#title").html("Question No "+counter);
                    $("#question").text(allQuestions[counter].question);
                    back();
                    for (var i = 0; i < allQuestions[counter].choices.length; i++) {
                        $('label[for=Option' + i + ']').html(allQuestions[counter].choices[i]);
                        if (answers["Q" + counter] == i) {
                            $("#Option" + i).prop('checked',true);
                        }

                        else {
                            $("#Option" + i).removeAttr('checked');
                        }
                    }
                };

                //this is the result screen giving the final amount of points
                function result() {
                    $("#title").html("Your Results");
                    for (var i = 0; i < allQuestions.length; i++) {
                        if (allQuestions[i].correctAnswer == answers["Q" + i]) {
                            points++;
                        }


                        $("#result").show().text("CONGRATULATIONS! You answered " + points + " out of " + allQuestions.length + " correct!");
                        $(".qbox").hide();
                        console.log(answers);

                    }
                }

                function welcome() {
                    // this is the welcome screen inviting to start the quizz
                    $("title").html("Welcome to the JQuery QuizY");
                    $(".qbox").hide();
                    $("#result").append().html("Random");
                    $("#result").append().html("<p id='start'>Start</p>");
                    $("#start").on('click', function () {
                        quiz();
                    });
                }

                function quiz() {
                    $("#start, #result").hide();
                    $(".qbox").show();
                    qload(counter);
                }
                $("#next").click(function () {
                    // this checks that one question is selected before processing
                    if ($('#Option0').is(':checked')) {
                        answers["Q" + counter] = 0;
                        ++counter;
                    }

                    else if ($('#Option1').is(':checked')) {
                        answers["Q" + counter] = 1;
                        ++counter;
                    }

                    else if ($('#Option2').is(':checked')) {
                        answers["Q" + counter] = 2;
                        ++counter;
                    }

                    else if ($('#Option3').is(':checked')) {
                        answers["Q" + counter] = 3;
                        ++counter;
                    }

                    else {
                        alert("Please make your selection before continuing!");
                    }

                    // this checks if there are any questions left, otherwise it goes to the result screen
                    if (allQuestions[counter]) {
                        qload(counter);
                    }
                    else {
                        result();
                    }
                });

                welcome();

            });

我已经进行了上述更改并在我的本地测试它并且它有效。

如果您遇到任何问题，请告诉我。

于 2013-07-22T08:00:54.207 回答