I have a form where I want to be able to do 2 different things depending on which button I press?

My form tag looks like this:
HTML Code:
<form id="mbpForm" method="post" action="admin.php?page=sitepages&ez=do_createpage" onsubmit="changeValues();">
At the bottom of my form I want 2 buttons. One ordinary submit button which do the action and then a button which changes the values using the changeValues() part....

How do I do this?

Thanks in advance ;-)