A client has sign up forms on their website but they only want business email addresses - i.e. NOT Gmail, Hotmail, Yahoo, etc.
Here’s are the custom attributes added to the input field to reject gmail, hotmail, yahoo:
pattern = "^((?!gmail)(?!yahoo)(?!hotmail).)*$"
title = "Please input a valid business email address. (i.e. NOT Gmail, Hotmail, Yahoo, etc)"