How to get the previous and next month?

Question

$year  = 2010;
$month = 10;

How do I get the previous month 2010-09 and next month 2010-11?

Answer 1

$date = mktime( 0, 0, 0, $month, 1, $year );
echo strftime( '%B %Y', strtotime( '+1 month', $date ) );
echo strftime( '%B %Y', strtotime( '-1 month', $date ) );