php 获取指定日期所在月份的最后一天

php 获取指定月最后一天：

<?php

function getthemonth($date)

{

$firstday = date('Y-m-01', strtotime($date));

$lastday = date('Y-m-d', strtotime("$firstday +1 month -1 day"));

return $lastday;

}

echo getthemonth('-5-16');

?>