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

strftime *:-* Format the time and/or date according to locale settings. Month and weekday names and other language-dependent strings respect the current locale set with setlocale().

strftime( '%B %Y', strtotime( '+1 month', $date ) );
strftime( '%B %Y', strtotime( '-1 month', $date ) );

Answer 2

PHP is awesome in this respect, it will handle date overflows by correcting the date for you...

$PreviousMonth = mktime(0, 0, 0, $month - 1, 1, $year);
$CurrentMonth = mktime(0, 0, 0, $month, 1, $year);
$NextMonth = mktime(0, 0, 0, $month + 1, 1, $year);

echo '<p>Next month is ' . date('Ym', $NextMonth) . 
    ' and previous month is ' . date('Ym', $PreviousMonth . '</p>';