HTML

input[type=time] datalist

<form action="../../form-result.php" method="post" target="_blank">

  <p>

    Choose the limit time: <input type="time" name="limittime" list="limittimeslist" step="0.001">

    <input type="submit" value="Send data">

  </p>

</form>

<datalist id="limittimeslist">

  <option value="06:40">

  <option value="08:24">

  <option value="12:31:30">

  <option value="23:59:59.999">

</datalist>

input[type=time] datalist

<form action="../../form-result.php" method="post" target="_blank">

  <p>

    Choose the limit time: <input type="time" name="limittime" list="limittimeslist" step="0.001">

    <input type="submit" value="Send data">

  </p>

</form>

<datalist id="limittimeslist">

  <option value="06:40">

  <option value="08:24">

  <option value="12:31:30">

  <option value="23:59:59.999">
  
  <option value="06:40">

  <option value="08:24">

  <option value="12:31:30">

  <option value="23:59:59.999">

<option value="06:40">

  <option value="08:24">

  <option value="12:31:30">

  <option value="23:59:59.999">


</datalist>