Submit button - make 2nd action dependent on first?

I have created a registration form and the submit form has two actions.

1. submit form

2. open confirmation page of our website

Both actions work, but if there is an error on the first (ex, not all required fields completed), the user clicks OK to acknowledge it. BUT instead of taking them back to the form to correct it, it opens the web page confirming their registration.

Is there a way to make the 2nd action work only if the first action is successful (error-free)?

Thanks!