php 获取当月/某月最后一天的时间戳

public function getendmouthtime()

    {

        $date=date("Y-m",time());

        $date_arr=explode('-',$date);

        $year=$date_arr[0];

        $month=$date_arr[1];

        $days_in_month = array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);

        if ($month 12)

        {

        return 0;

        }

        // Is the year a leap year?

        if ($month == 2)

        {

            if ($year%400 == 0 OR ($year%4 == 0 AND $year%100 != 0))

            {

            return $year.'-'.$month.'-29';

            }

        }

        return $endstro = strtotime($year.'-'.$month.'-'.$days_in_month[$month - 1]);

    }