Php 如何在提交页面后单击单选按钮

问题

**question_id  question  option1 option2 option3 option4   answer** 
15          AAA         a1     a2      a3       a4           3
38          BBB         b1     b2      b3       b             2
39          CCC         c1     c2      c3       c4            4
44          DDD         d1     d2      d3       d4            2
45          EEE         e1     e2      e3       e4            1

start\u exam.php

$query="select * from exam_question_list where exam_paper_id='$exam_paper_id'";
$result=mysqli_query($dbcon,$query);
$row = mysqli_fetch_array($result);
$que1=$row['q1'];

<form action="exam_paper_result.php?1=<?php echo $row['q1'];?>>
<?php 
    $sql1="SELECT question_id AS qid, question AS q, option1 AS op1, option2 AS op2, option3 AS op3, option4 AS op4 FROM question where question_id='$que1'";


        $data1=mysqli_query($dbcon,$sql1);

    while($datan1 = mysqli_fetch_array($data1)){

        $i=0;
?>
  <tr>
     <tr data-label="Question"><td><span>(01)&nbsp;&nbsp;</span><?php echo $datan1['q'];  ?></td></tr>
      <tr data-label="Question"><td><input type="radio"  name="a1" value="1"/><?php echo $datan1['op1']; ?></td></tr>
      <tr data-label="Question"><td><input type="radio"  name="a1" value="2"/><?php echo $datan1['op2']; ?></td></tr>
      <tr data-label="Question"><td><input type="radio"  name="a1" value="3"/><?php echo $datan1['op3']; ?></td></tr>
      <tr data-label="Question"><td><input type="radio"  name="a1" value="4"/><?php echo $datan1['op4']; ?></td></tr>  

    </tr>


<?php
    }
    ?>

 <input name="submit" type="submit" id="Submit" value="Submit"/>
</form>

if (isset ($_POST['submit'])) {


$qu1 =$_GET['1'];
$q1 =  $_POST['a1'];

$score ="";

$sql1="SELECT question_id AS qid, answer AS a FROM question where question_id='$qu1'";
$result1=mysqli_query($dbcon,$sql1);
$row1=mysqli_fetch_array($result1);

if (!isset($q1)) {
 echo("Error: please specify a type, new or old");
 //$score = 0;

 } else {

if($row1['a'] == $q1){
    echo "correct";
    //$score = 1;

}else{
    echo "wrong";
    //$score = 1;
}   
}

 }
  ?>

选择正确选项后，打印“正确” 当我选择错误选项时，请打印“错误” 当我没有选择任何选项并单击提交时；有一个错误

“注意：第38行G:\xampp\htdocs\examice\u system\src\applicator\examine\paper\u result.php中未定义的索引：a1

---

错误：未选择任何答案“

当未选中单选按钮时，它可能会在此行中显示通知：

$q1 =  $_POST['a1'];

将其更改为：

 $q1 =  isset($_POST['a1']) ? $_POST['a1'] : NULL; 

---

确定变量是否已设置且不为空。所以你需要使用isset函数

 $q1 = null;    
 if(isset($_POST['a1'])){
 $q1 = $_POST['a1'];
}

你也可以使用这个条件

$q1 = isset($_POST['a1']) ? $_POST['a1'] : null;

如果您需要任何这样的收音机类型，那么您不能在未检查任何收音机的情况下提交此表格

<form>
<label for="input1">Label 1:</label>
<input type="radio" name="radio" id="input1" value="1" required>     <br>

<label for="input2">Label 2:</label>
 <input type="radio" name="radio" id="input2" value="2"><br>

<label for="input3">Label 3:</label>
<input type="radio" name="radio" id="input3" value="3"><br>

<input type="submit" value="send">
</form>

标签1：


标签2：


标签3：

有关更多信息，请查看此项

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你能更清楚地解释一下吗？“start_exam.php”中有一个问题和4个选项，我想为这个问题设置分数，当我没有选择任何选项并单击提交时，我想在“result.php”中打印“empty”，在输入中添加必填项，我想这会解决所有问题