Add fields to Paypal Cancel form

I ran across this post on the old forum: https://www.s2member.com/forums/topic/custom-cancel-form-field-authnet-pro-forms/index.html

We would like to do the same - to provide a text field for a customer to tell us why they are canceling. Has this capability been added, or how might we do so? Custom coding/PHP not a problem if required.

We are using Pro.

Try to create a custom template, maybe?

Not super simple in this case. The PayPal cancellation form (we’re using PayPal) contains a number of values like “attr” and “nonce” that are custom and/or hashes of something, so we really need to work with the existing form architecture if possible.

I suppose we could do something like use javascript to inject a field into the existing form, but then we’d need to handle that field on the submit side.

Is there a way to hook into the submission of a cancellation form, so we can write the value of this field to user meta?

What about an AJAX call to your (contact form?) code just before the submission of the form to Paypal?