I have a number of stateless forms that have mandatory fields which are required to perform an action (e.g. insert records into another form or send an email)

I want to create a custom cancel button with the only action:

However, when I click this button, I'm prompted to fill in all of the required fields on the form.

Of course I want to be prompted to fill in the required fields if I'm clicking my 'Submit' or 'send mail' button, but - how can I bypass this validation in certain action scripts such as to close the form?

Thanks!