Well, theres no such thing as a "save" button in HTML forms. You can label your SUBMIT button to say "SAVE", but it is going to POST the form data for each page to the designated ACTION script.
My suggestion: every time one of the form "pages" is posted, have the ACTION script save the form data as session variables and then present the next "page". When they post the last page, cycle through the session vars to validate. If there are errors, construct a form showing the invalid data and fields so that they can be corrected.
-- Rich