php禁用动态下拉菜单中的特定选项

<form method="POST" action="your_php_script.php">
  <select name="dropdown">
    <option value="option1">Option 1</option>
    <option value="option2">Option 2</option>
    <option value="option3">Option 3</option>
  </select>
  <input type="submit" value="Submit">
</form>

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $selectedOption = $_POST["dropdown"];
  
  // 判断用户选择的选项并禁用特定选项
  if ($selectedOption == "option2") {
    echo '<script>alert("Option 2 is disabled.");</script>';
  }
}
?>