javascript - Ajax请求未执行返回未定义

Question

我正在设计一个在线多项选择测试，以便用户选择 3 个答案之一(单选按钮)，然后提交他/她的答案。按下提交按钮后，我需要计算结果，我使用 AJAX 请求分别比较每个答案，并使用 PHP 脚本，该脚本还根据 AJAX 请求参数一一检索问题。

这是我的 AJAX 请求:

function calculateResults(){
  totalPoints = 0;
  var qNum = 10;
  while(qNum != 0){
  $.ajax({
      method : "GET",
      url: "php-scripts/testing-questions.php",
      data: {queNum : qNum},
      success: function(data){
          console.log(data);
          //check if radio1 value is set
          if(document.getElementById('r1q' + qNum).check == true){
            var answer = document.getElementById('r1q' + qNum).value;
          }
          //check if radio2 value is set
          else if(document.getElementById('r2q' + qNum).check == true){
            var answer = document.getElementById('r2q' + qNum).value;
          }
          else{ //radio 3 value is set then
             var answer = document.getElementById('r3q' + qNum).value;
          }
          if(data === answer){
              totalPoints++;
          }
        }
     });
     qNum--;
  }

}

这是我的 PHP 脚本

if(isset($_GET['queNum'])){
    $qNum = $_GET['queNum'];
    getAnswer($qNum);
      function getAnswer($num){
          $query = mysqli_query($conn, "SELECT correctAnswer
                              FROM  `Testing` 
                              WHERE  `questionNum` = '".$queNum."' ");
          $row = mysqli_fetch_array($query,MYSQLI_ASSOC);
          echo $row;
          $correA = $row['correctAnswer'];
          echo $correA;
      }
}

请注意， $conn 变量是从 config.php 文件中设置的，您可以正确地假设与数据库的连接工作正常，并且函数中的 echo 语句也存在用于调试原因，您也应该假设SQL 查询也运行良好。

我已经为此工作了一天多，试图找出问题所在，它看起来很简单，但我无法让它工作，并且这里或其他任何地方都没有关于 AJAX 退出未定义的其他示例。任何有更多信息的人非常感谢您的经验。

按照以下要求的 HTML 代码:

 <div class="container3">
<div id="startTest">
  <center><button class="checkButtons" onClick="startTimer()" style="width:100px;"> Start Test</button></center>
</div>
<div id="beginTest">
 <input type = "text" name="timer" width="30%" id="timer" value ="10:00" readonly>
</div>
<div id="questions">
 <center>
  <div class="question">
    <p class="q">Question 1: <?php echo $question1 ?></p>
    <input type="radio" id="r1q1" name="answer1" value="Answer 1" checked>Answer A: <?php echo $answerA1 ?> <br>
    <input type="radio" id="r2q1" name="answer1" value="Answer 2">Answer B: <?php echo $answerB1 ?> <br>
    <input type="radio" id="r3q1" name="answer1" value="Answer 3">Answer C: <?php echo $answerC1 ?> <br>
  </div>
   <div class="question">
    <p class="q">Question 2: <?php echo $question2 ?></p>
    <input type="radio" id="r1q2" name="answer2" value="Answer 1" checked>Answer A: <?php echo $answerA2 ?> <br>
    <input type="radio" id="r2q2" name="answer2" value="Answer 2">Answer B: <?php echo $answerB2 ?> <br>
    <input type="radio" id="r3q2" name="answer2" value="Answer 3">Answer C: <?php echo $answerC2 ?> <br>
  </div>
   <div class="question">
    <p>Question 3: <?php echo $question3 ?></p>
    <input type="radio" id="r1q3" name="answer3" value="Answer 1" checked>Answer A: <?php echo $answerA3 ?> <br>
    <input type="radio" id="r2q3" name="answer3" value="Answer 2">Answer B: <?php echo $answerB3 ?> <br>
    <input type="radio" id="r3q3" name="answer3" value="Answer 3">Answer C: <?php echo $answerC3 ?> <br>
  </div>
  <div class="question">
  <p class="q">Question 4: <?php echo $question4 ?></p>
    <input type="radio" id="r1q4" name="answer4" value="Answer 1" checked>Answer A: <?php echo $answerA4 ?> <br>
    <input type="radio" id="r2q4" name="answer4" value="Answer 2">Answer B: <?php echo $answerB4 ?> <br>
    <input type="radio" id="r3q4" name="answer4" value="Answer 3">Answer C: <?php echo $answerC4 ?> <br>
  </div>
   <div class="question">
    <p class="q">Question 5: <?php echo $question5 ?></p>
    <input type="radio" id="r1q5" name="answer5" value="Answer 1" checked>Answer A: <?php echo $answerA5 ?> <br>
    <input type="radio" id="r2q5" name="answer5" value="Answer 2">Answer B: <?php echo $answerB5 ?> <br>
    <input type="radio" id="r3q5" name="answer5" value="Answer 3">Answer C: <?php echo $answerC5 ?> <br>
  </div>
   <div class="question">
   <p class="q">Question 6: <?php echo $question6 ?></p>
    <input type="radio" id="r1q6" name="answer6" value="Answer 1" checked>Answer A: <?php echo $answerA6 ?> <br>
    <input type="radio" id="r2q6" name="answer6" value="Answer 2">Answer B: <?php echo $answerB6 ?> <br>
    <input type="radio" id="r3q6" name="answer6" value="Answer 3">Answer C: <?php echo $answerC6 ?> <br>
  </div>
   <div class="question">
    <p class="q">Question 7: <?php echo $question7 ?></p>
    <input type="radio" id="r1q7" name="answer7" value="Answer 1" checked>Answer A: <?php echo $answerA7 ?> <br>
    <input type="radio" id="r2q7" name="answer7" value="Answer 2">Answer B: <?php echo $answerB7 ?> <br>
    <input type="radio" id="r3q7" name="answer7" value="Answer 3">Answer C: <?php echo $answerC7 ?> <br>
  </div>
   <div class="question">
   <p class="q">Question 8: <?php echo $question8 ?></p>
    <input type="radio" id="r1q8" name="answer8" value="Answer 1" checked>Answer A: <?php echo $answerA8 ?> <br>
    <input type="radio" id="r2q8" name="answer8" value="Answer 2">Answer B: <?php echo $answerB8 ?> <br>
    <input type="radio" id="r3q8" name="answer8" value="Answer 3">Answer C: <?php echo $answerC8 ?> <br>
  </div>
   <div class="question">
   <p class="q">Question 9: <?php echo $question9 ?></p>
    <input type="radio" id="r1q9" name="answer9" value="Answer 1" checked>Answer A: <?php echo $answerA9 ?> <br>
    <input type="radio" id="r2q9" name="answer9" value="Answer 2">Answer B: <?php echo $answerB9 ?> <br>
    <input type="radio" id="r3q9" name="answer9" value="Answer 3">Answer C: <?php echo $answerC9 ?> <br>
  </div>
   <div class="question">
    <p class="q">Question 10: <?php echo $question10 ?></p>
    <input type="radio" id="r1q10" name="answer10" value="Answer 1" checked>Answer A: <?php echo $answerA10 ?> <br>
    <input type="radio" id="r2q10" name="answer10" value="Answer 2">Answer B: <?php echo $answerB10 ?> <br>
    <input type="radio" id="r3q10" name="answer10" value="Answer 3">Answer C: <?php echo $answerC10 ?> <br>
  </div>
    <button class="checkButtons" onClick="calculateResults()" style="width:100px;"> Submit Answers</button>
</center>
</div>

Answer 1

乍一看，您的代码没有显示任何问题。

您的 PHP 脚本应该是。 getAnswer($num) 应该是 getAnswer($qNum) 在查询中，应该使用 $qNum 变量而不是 $queNum。

 if(isset($_GET['queNum'])){
        $qNum = $_GET['queNum'];
        getAnswer($qNum);
          //$qNum not $num
          function getAnswer($qNum){
              $query = mysqli_query($conn, "SELECT correctAnswer
                                  FROM  `Testing` 
                                  WHERE  `questionNum` = '".$qNum."' ");
              $row = mysqli_fetch_array($query,MYSQLI_ASSOC);
              $correA = $row['correctAnswer'];
              echo $correA;
              exit;
          }
    }