php獲取當前月的天數

<?php
    //php獲取當前月份的所有天數
    $start_day = date('Ym01', time());
    $end_day   = date('Ymd', strtotime("{$start_day} + 1 month -1 day"));

　　 $date = range($start_day, $end_day, 1);

    var_dump($date);