get day of month php

1$month = date("m",strtotime($mydate));

1$dayofweek = date('w', strtotime($date));
2$result    = date('Y-m-d', strtotime(($day - $dayofweek).' day', strtotime($date)));

1$lastDateOfNextMonth =strtotime('last day of next month') ;
2
3$lastDay = date('d/m/Y', $lastDateOfNextMonth);
4
5 
6
7print_r($lastDay);

1// get day of month php
2// Method 1; some server not work, I had check php 7.3.24 not worked, php 7.3.8 worked
3cal_days_in_month(CAL_GREGORIAN, $month, $year)
4echo (cal_days_in_month(CAL_GREGORIAN, 2, 2020)); // => 29
5
6// Method 2;
7function days_in_month($month, $year) {
8    // calculate number of days in a month
9    return $month == 2 ? ($year % 4 ? 28 : ($year % 100 ? 29 : ($year % 400 ? 28 : 29))) : (($month - 1) % 7 % 2 ? 30 : 31);
10}
11
12// Method 3;
13echo (date('t', strtotime('2020-02-1')));	// 29
14
15
16

1echo cal_days_in_month(CAL_GREGORIAN, 8, 2009);
2

1$mydate = '2016-01-01';
2echo date('l, F jS, Y', strtotime($mydate));
3# Friday, January 1st, 2016
4