- mktime: documentation ( source)
- date: documentation ( source)
<?php
$month = 9;
$year = 2014;
$start = mktime(0, 0, 0, $month, 1, $year);
$now = $start;
while (date('n', $now) != $month) {
echo date('Y-m-d l', $now) . PHP_EOL;
$now += 86400;
}