Html PHP Post表单未将Select或Datepicker元素传递到电子邮件

我之前确实做过一次搜索，但没有找到与我所经历的问题相似的东西。我最近使用表单元素和PHP设置了一个表单到POST方法。我可以确认我正在接收电子邮件和其他字段的信息，但是

和Jquery“datepicker”元素没有向电子邮件传递任何信息，它们解析为空白

HTML代码如下所示：

 <form method="POST" action="mail.php" id="contactform" class="centered">
    <fieldset>
      <input type="text" name="first_name" placeholder="First Name" required>
      <div class="controls controls-row">
        <input type="text" name="last_name" placeholder="Last Name" required>
      </div>
      <input type="email" name="email" placeholder="Email Address" required>
      <div class="controls-row">
        <input type="text" id="datepicker" name="check_in" placeholder="Check-in" required> 
      </div>  
      <div class="controls-row">
        <input type="text" id="datepicker2" name="check_out" placeholder="Check-out" required>
      </div>      
      <div class="controls-row">
        <select id="modalselect" name="rooms">
          <option value="0" selected="selected">Number of Rooms</option>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
          <option value="4">4</option>
          <option value="5">5+</option>
        </select>  
      </div>
      <div class="controls-row">
        <select id="modalselect" name="people">
          <option value="0" selected="selected">Number of People</option>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
          <option value="4">4</option>
          <option value="5">5</option>
          <option value="6">6</option>
          <option value="7">7</option>
          <option value="1">8</option>
          <option value="2">9</option>
          <option value="3">10+</option>
        </select>
      </div>

      <textarea rows="3" name="additional" input class="input-xparge" placeholder="Anything else?" class="span5"></textarea>
    </fieldset>    
  </form>  
</div>

<div class="modal-footer">
  <button type="submit" name="submit" input type="submit" form="contactform" class="btn btn-block btn-large btn-success"  value="submit">Submit</button>

<?php
$first_name = $_POST['first_name'];
$last_name = $_POST['last_name'];
$email = $_POST['email'];
$check_in = $POST['check_in'];
$check_out = $POST['check_out'];
$rooms = $POST['rooms'];
$occupants = $POST['people'];
$additional = $_POST['additional'];
$from = "From: Babbacombe Hall Mailserver";
$to = "lloyd.rees09@bathspa.ac.uk";
$subject = "New Booking Enquiry";

$body = "First Name: $first_name\n Last Name: $last_name\n Email: $email\n Check In: $check_in\n Check Out: $check_out\n Number of Rooms: $rooms\n Number of Occupants: $occupants\n Additional Information: $additional"; 

if ($_POST['submit']) {
 if (mail ($to, $subject, $body, $from)) { 
     echo '<p>Your message has been sent!</p>';
   } else { 
       echo '<p>Something went wrong, go back and try again!</p>'; 
   }
}

房间数
1.
2.
3.
4.
5+
人数
1.
2.
3.
4.
5.
6.
7.
8.
9
10+
提交

PHP代码如下：

 <form method="POST" action="mail.php" id="contactform" class="centered">
    <fieldset>
      <input type="text" name="first_name" placeholder="First Name" required>
      <div class="controls controls-row">
        <input type="text" name="last_name" placeholder="Last Name" required>
      </div>
      <input type="email" name="email" placeholder="Email Address" required>
      <div class="controls-row">
        <input type="text" id="datepicker" name="check_in" placeholder="Check-in" required> 
      </div>  
      <div class="controls-row">
        <input type="text" id="datepicker2" name="check_out" placeholder="Check-out" required>
      </div>      
      <div class="controls-row">
        <select id="modalselect" name="rooms">
          <option value="0" selected="selected">Number of Rooms</option>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
          <option value="4">4</option>
          <option value="5">5+</option>
        </select>  
      </div>
      <div class="controls-row">
        <select id="modalselect" name="people">
          <option value="0" selected="selected">Number of People</option>
          <option value="1">1</option>
          <option value="2">2</option>
          <option value="3">3</option>
          <option value="4">4</option>
          <option value="5">5</option>
          <option value="6">6</option>
          <option value="7">7</option>
          <option value="1">8</option>
          <option value="2">9</option>
          <option value="3">10+</option>
        </select>
      </div>

      <textarea rows="3" name="additional" input class="input-xparge" placeholder="Anything else?" class="span5"></textarea>
    </fieldset>    
  </form>  
</div>

<div class="modal-footer">
  <button type="submit" name="submit" input type="submit" form="contactform" class="btn btn-block btn-large btn-success"  value="submit">Submit</button>

<?php
$first_name = $_POST['first_name'];
$last_name = $_POST['last_name'];
$email = $_POST['email'];
$check_in = $POST['check_in'];
$check_out = $POST['check_out'];
$rooms = $POST['rooms'];
$occupants = $POST['people'];
$additional = $_POST['additional'];
$from = "From: Babbacombe Hall Mailserver";
$to = "lloyd.rees09@bathspa.ac.uk";
$subject = "New Booking Enquiry";

$body = "First Name: $first_name\n Last Name: $last_name\n Email: $email\n Check In: $check_in\n Check Out: $check_out\n Number of Rooms: $rooms\n Number of Occupants: $occupants\n Additional Information: $additional"; 

if ($_POST['submit']) {
 if (mail ($to, $subject, $body, $from)) { 
     echo '<p>Your message has been sent!</p>';
   } else { 
       echo '<p>Something went wrong, go back and try again!</p>'; 
   }
}

非常感谢您的帮助和专业知识
 替换这个：

$check_in = $POST['check_in'];
$check_out = $POST['check_out'];
$rooms = $POST['rooms'];
$occupants = $POST['people'];

为此：

$check_in = $_POST['check_in'];
$check_out = $_POST['check_out'];
$rooms = $_POST['rooms'];
$occupants = $_POST['people'];

非常感谢你！我不敢相信我打错了$\u POST。真的还不习惯用其他语言编码。