javascript - 表单提交后如何保持动态下拉菜单的值保持选中状态？

Question

请帮我在提交表单后显示所选的电子邮件。请查看下面提到的代码:

<?php
    $query= mysqli_query($conn," SELECT email FROM register");
    $options="";
    $result=mysqli_fetch_assoc($query);
    if(mysqli_num_rows($query) >0)
    {
       while($row=mysqli_fetch_array($query))
       {
         $options = $options."<option>$row[0]</option>";
       }
   }
?>
<select name="email" id="email">
<option value="" disabled="" selected="">SELECT EMAIL</option>
<?php echo $options;?>
</select> 

Answer 1

    <select name="email" id="email">
    <option value="" disabled="" selected="">SELECT EMAIL</option>
    <?php
    $query= mysqli_query($conn," SELECT email FROM register");
    $result=mysqli_fetch_assoc($query);
    if(mysqli_num_rows($query) >0)
    {
       while($row=mysqli_fetch_array($query))
       {
         echo "<option value='<?=$row[0]?>'><?= $row[0]?></option>";
       }
   }
     ?>
    </select>