php last day of month

$currentMonth = date('M');// if number, then date('m');
//Last month
$lastMonth = Date("F", strtotime("first day of previous month");
$nextMonth = Date("F", strtotime("first day of next month");

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

$lastDay = date('t',strtotime('last month'));

print_r($lastDay);

$lastDateOfNextMonth =strtotime('last day of next month') ;

$lastDay = date('d/m/Y', $lastDateOfNextMonth);

 

print_r($lastDay);

//Last month
$lastMonth = Date("F", strtotime("first day of previous month");
$nextMonth = Date("F", strtotime("first day of next month");