PHP中的单选按钮不能正常工作 - Radio buttons in PHP not working properly

Radio buttons in PHP not working properly

我有这样的代码:

<?php 
if (isset($_POST['ans'])) {
    $answer = $_POST['ans']; 
    if ($answer == "answers1") {          
        echo 'Correct';      
    }
    else {
        echo 'Incorrect';
    }
}
?>
<form action="example.php" method="post">
  Answer 1 <input type="radio" name="answers" value="answers1" /><br />
  Answer 2 <input type="radio" name="answers" value="answers2"  /><br />
  Answer 3 <input type="radio" name="answers" value="answers3"  /><br />
  Answer 4 <input type="radio" name="answers" value="answers4"  /><br />
  <input type="submit" value="submit" />
</form>

当我选择错误的按钮时，它告诉我错误，当我选择正确的按钮时，它告诉我正确。问题是，如果没有选择按钮，什么也不会发生。它不会重复不正确或正确。

尝试添加else if，这样如果选定的按钮为空，它将传递给它。

    <?php
if (isset($_POST['ans'])) {
    $answer = $_POST['ans']; 
    if ($answer == "answers1") {          
        echo 'Correct';      
    }
    else if(empty($answer)){
        echo 'Select Button';
    }
    else {
        echo 'Incorrect';
    }
}
?>

不检查$_POST['ans']检查是否有内容发布:

if ('POST' === $_SERVER['REQUEST_METHOD']) {
    $answer = isset($_POST['ans']) ? $_POST['ans'] : false;
    if ($answer == "answers1") {          
        echo 'Correct';      
    }
    else {
        echo 'Incorrect';
    }
}

另一种方法是添加另一个隐藏输入并检查