JavaScript 数组以传递 HTML 无线电的默认值

Question

我对测验应用程序有疑问。我是新手，我的问题是我不知道如何从 JS 数组中给输入类型无线电默认值。因此，当页面加载时，您已经可以看到 array[0] 位置值作为选项。

HTML代码：

<p>
<p id="question"></p>
</p>
  <input type="radio" name="quiz" id="ans1" >
   <br>
  <input type="radio" name="quiz" id="ans2">
  <br>
  <input type="radio" name="quiz" id="ans3">
  <br>
  <input type="radio" name="quiz" id="ans4">
  <br>
<input type="submit" value="Start" onClick="RadioCheck()">
</form>

JS代码：

<script language="javascript">

var allQuestions = [{
    question: "Question1?", 
    choices: ["Answer1", "Answer2", "Answer3", "Answer4"],
    CorrectAnswer:0},
    {
    question: "Question2?", 
    choices: ["Answer1", "Answer2", "Answer3", "Answer4"],
    CorrectAnswer:0},
    {
    question: "Question3?", 
    choices: ["Answer1", "Answer2", "Answer3", "Answer4"],
    CorrectAnswer:0},
    {
    question: "Question4?", 
    choices: ["Answer1", "Answer2", "Answer3", "Answer4"],
    CorrectAnswer:0}
    ];

var currentQuestion=0;
var CorrectAnswer=0;


function RadioCheck() {
//populate question in HTML
    var question = document.getElementById("question");
    question.nextSibling.data = allQuestions[currentQuestion].question;

//populate answers in HTML
    var ans1 = document.getElementById("ans1");
    ans1.nextSibling.data = allQuestions[currentQuestion].choices[0];

    var ans2 = document.getElementById("ans2");
    ans2.nextSibling.data = allQuestions[currentQuestion].choices[1];

    var ans3 = document.getElementById("ans3");
    ans3.nextSibling.data = allQuestions[currentQuestion].choices[2];

    var ans4 = document.getElementById("ans4");
    ans4.nextSibling.data = allQuestions[currentQuestion].choices[3];

    var selection = document.getElementsByTagName('input')

    if(selection[allQuestions[currentQuestion].CorrectAnswer].checked == true ){
      CorrectAnswer ++;
    } 

     currentQuestion ++;
} 

</script>

这在我第一次单击“开始”按钮时有效，但我想在页面加载后立即显示问题 1 和答案。

Answer 1

您需要为 onload 事件添加一个函数。

例如，在您的正文声明中，您可以添加以下内容

<body onload="RadioCheck()">

页面加载时，RadioCheck 函数将运行填充您的表单。

您可以在此处找到有关 onload 事件的更多信息：http://www.w3schools.com/jsref/event_onload.asp

JavaScript 数组以传递 HTML 无线电的默认值

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