PHP - Date with with ms

PHP - date with ms.php

<?php
  function udate($format, $utimestamp = null) {
    if (is_null($utimestamp))
      $utimestamp = microtime(true);
  
    $timestamp = floor($utimestamp);
    $milliseconds = round(($utimestamp - $timestamp) * 1000000);
  
    return date(preg_replace('`(?<!\\\\)u`', $milliseconds, $format), $timestamp);
  }
?>