get month last and first day even leap year

Get last day of month with php date.

echo date('t',strtotime('25-02-2016'));
//its return 29

echo date('t',strtotime('25-02-2015'));
//its return 28

echo date('t',strtotime('11-10-2015'));
//its return 30

Get Frist day of month.

echo date('D',strtotime('01-11-2013'));
//its return 01