Custom Form Validation Rule

[eluser]dennismonsewicz[/eluser]
Is there anyway to write your own rule so that you can check if a certain value is greater than or equal to another value?

I am wanting to check a birthday year field and am wanting to make sure that the submitted birthday year is greater than a certain age.

[eluser]verynewtothis[/eluser]
I think you are looking for callbacks:
Callbacks - your own validation functions