“phpfiddle” Ответ

phpfiddle

<form action="../../form-result.php" method="post" target="_blank">
  <p>
    Desired time to receive the call: <input type="time" name="desiredcalltime" list="calltimeslist">
    <input type="submit" value="Send data">
  </p>
</form>
<datalist id="calltimeslist">
  <option value="16:00">
  <option value="16:30">
  <option value="17:00">
  <option value="17:30">
</datalist>