PHP获得月初月末时间戳，或得指定月份天数

/*获得月初月末时间戳*/

$thismonth = date('m');

$thisyear = date('Y');

$startDay = $thisyear . '-' . $thismonth . '-1';

$endDay = $thisyear . '-' . $thismonth . '-' . date('t', strtotime($startDay));

$month_start  = strtotime($startDay);

$month_end  = strtotime($endDay);

/*获得指定月份天数*/

cal_days_in_month(calender,$month,$year)；