function getMillisecond() {
  list($t1, $t2) = explode(' ', microtime());
  return (float)sprintf('%.3f',(floatval($t1)+floatval($t2)));
}

function getMillisecond1() {
  list($t1, $t2) = explode(' ', microtime());
  return (float)sprintf('%.0f',(floatval($t1)+floatval($t2))*1000);
}

echo '毫秒級時間戳保留三位小數：'.getMillisecond()."<br/>";
echo '毫秒級時間戳保留零位小數：'.getMillisecond1()."<br/>";

$a = cal_days_in_month(CAL_GREGORIAN, 3, 2016);echo "<br/>".$a;die;