Postcode field in form fields

How To
1

I would like to check the field postcode. Is there a way to do this currently?
Our postcode are like 1234AA format.
Using regex would do the trick but can’t find a way to do this

var rege = /^[1-9][0-9]{3} ?(?!sa|sd|ss)[a-z]{2}$/i;

2

I think you’d need custom validation: