How to compare dates (i.e. 12/12/2005 with 11/12/2005)

I have 2 fields that take in date fields (MM/DD/YYYY) and I need to make sure that the second date input is correct in that it comes after the first date.
For example:

12/12/2005
11/12/2005
this would result in a fail, because the second date (11/12/2005) comes before the first date (12/12/2005).

 

Change the date to a timestamp and then compare (they are just ints).

if (mktime (0,0,0,12,12,2005) <= mktime (0,0,0,11,12,2005)) {
      // fail
} else {
      // dates are good
}

PHP:

 

Thank you!

 

You're welcome!