As part of my registration process, I have a dropdown box in which a 4 integer number is selected. As a confirmation, I then have the user enter the same 4 integers into a text box. The text box uses a Regexp format. Is it possible to have the textbox entry compared to the dropdown selection and then notify the user if the two entries do not match?

This is similar in operation to the email confirmation custom field that you already provide.

If you do not have this feature, do you know of a 3rd party component compatible with EasySocial that does this error checking?