Regular Expression to match a valid day in a date

Question

I need help coming up with a regex to make sure the user enters a valid date The string will be in the format of mm/dd/yyyy

Here is what I have come up

Answer 1

Regex for 0-31:

(0[1-9]|[12]\d|3[01])

Or if you don't want days with a preceding zero (e.g. 05):

([1-9]|[12]\d|3[01])