How to get months name and month days between two differente dates?

Please try it.

$start_date  = '2015-11-15';
$end_date  = '2015-12-25';
$result = array();
$start_time   = strtotime($start_date);
$end_time   = date('m-Y', strtotime($end_date));
do {
$month_year = date('m-Y', $start_time);
$days = date('t', $start_time);
$result[] = [
'month_year' => $month_year,
'days' => $days,
];
$start_time = strtotime('+1 month', $start_time);
} while ($month_year != $end_time);