Is this a PHP date() bug, or is there something wrong with my code?

Question

I\'ve two images of an arrow, one which increments the month backward, one which increments it forward via href.

if (ISSET($_GET[\"month\"])){
    $month_in         


        

Answer 1

There is no February 29th in 2015.

By just adding or subtracting whole months at a time, you create new dates on the same day in the requested month. In this case, you caused PHP to try and make a February 29, 2015 date. It automatically jumped forward to March 1, 2015.

If you only care about Months, create dates on the first of each month:

date("F y", mktime(0,0,0, $month_index, 1, 2015));

Good thing you are writing this code and caught the bug today, or you would have had a bug that only appeared on the 29th (or 31st) of every month (except leap years)!

Dates are hard.