php get first day of last month code example

Example 1: get next month first day php

$config_month  = 1;
$config_day = 1;

$new_expiry_date = date('Y-m-d', mktime(0, 0, 0, date('m') + $config_month, 1 + $config_day, date('Y')));

Example 2: php last day of month

$a_date = "2009-11-23";
echo date("Y-m-t", strtotime($a_date));