[curtiss]

The easiest way in PHP is to convert your date into a timestamp (look up the strtotime function), then add the number of seconds to the timestamp. Then, you can convert your timestamp back into a date string.

Timestamps are calculated by the number of seconds from midnight on January 1, 1970. Therefore, a timestamp of "60" would be 00:01:00 on Jan. 1, 1970. If you add your current timestamp (which you can get using the Now() function in PHP) plus the number of seconds you want to add (300, 1000, or 3000), you'll get the correct time.