<pre>
<?php
print_r($_POST);
?>
</pre>

<?php
$servername = "localhost";
$username = "root";
$password = "";
$dbname = "adrian_wedding";



// Create connection
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

$stmt = $conn->prepare("INSERT INTO rsvp VALUES (?, ?, ?, ?, ?)");
$stmt->bind_param('ssss', $_POST['firstname'], $_POST['lastname'], $_POST['attendance'], $_POST['dish'], $_POST['special_diet']);

$stmt->execute();
$stmt->close();

/* close connection */
$conn->close();
?>

<div id="id01" class="w3-modal w3-card w3-animate-opacity">
    <div class="w3-modal-content w3-display-middle">
          <header class="w3-container w3-teal">
              <span onclick="document.getElementById(\'id01\').style.display=\'none\'"
                  class="w3-button w3-display-topright">&times;</span>
                          <h2>RSVP</h2>
                              <p>Please fill out one RSVP form for each guest.</p>
                                </header>
                                  <div class="w3-container w3-center">
                                          <form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">

<div>
<style>
.text_area {margin: 10px;}
</style>
<div class="text_area">
First name:<input type="text" name="firstname" value="<?php echo $_POST['firstname']; ?>">
</div>
<div class="text_area">
Last name: <input type="text" name="lastname" value="<?php echo $_POST['lastname']; ?>">
</div>
</div>
<div>
<input type="radio" name="attendance" value="will_be_attending"> I will be attending
<input type="radio" name="attendance" value="will_not_be_attending"> I will not be attending
</div>
<br>
Please Select your dish
<select name="dish">
  <option value="beef">Beef Tenderloin</option>
  <option value="chicken">Chicken Supreme Marseillaise</option>
  <option value="salmon">Pan Seared Wild Salmon Filet</option>
</select>

<p>Plese let us know if you have any special diatary needs</p>
<textarea name="special_diet" rows="5" cols="60"></textarea><br>
<br>
<input type="submit" value="Submit"><br>
<br>
</form>
      </div>
      <footer class="w3-container w3-teal">
        <br>
      </footer>
    </div>
  </div>