how to get month end date in php code example

Example 1: php grab month from date

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

Example 2: php get start and end date of month and year

<?php

$query_date = '2010-02-04';

// First day of the month.
echo date('Y-m-01', strtotime($query_date));

// Last day of the month.
echo date('Y-m-t', strtotime($query_date));