strtotime on incorrect dates

Question

I found something odd about strtotime().

On dates that do not exist it returns the day after.

$d30= strtotime(\"2017-06-30\");
Echo $d30 .\"\\n\";
         


        

Answer 1

As day 31 of a month is possible strtotime() will correct the date for you. If you try it with February (2017-02-31) it will correct to 2017-03-03. This is what you found.

So, what it essentially does is:

1. get the date
2. check if the date is in a valid range (days per month)
3. if not valid count days into the next month

This behaviour is implemented into the strtotime function itself.

There was a great comment on the documentation page about this, but I am no longer able to find it. This comment provides some extra information (be sure to check the link in the comment).