- var_dump: documentation ( source)
- mktime: documentation ( source)
- date: documentation ( source)
- strtotime: documentation ( source)
<?php
$start = strtotime('2014-10-05');
$end = strtotime('2014-10-31');
$stamp = $start;
$months = array();
do {
$next_stamp = mktime(0,0,0, date('n',$stamp)+1, 1, date('Y',$stamp));
$months[] = ($next_stamp-$stamp)/3600/24/date('t', $stamp);
$stamp = $next_stamp;
} while ($stamp < $end);
var_dump($months);