credit card issue

Hi all, I did write a form in php for customer to purchase things and it contains credit card number. I tested it and realise that after I submit the form, and redirect the page to another page, If I click the "back" button of the browser ( using IE 5.0 ) to come back to the form, I found that the credit card detail was still there. The credit card page is on secure server by the way. Is there anyway I can solve this problem? Any help will be greatly appreciated. Jack jacky@activelifestyle.com "Power is nothing without control