Stop browser from remembering form data

Hi there,

 I have a page that collects credit card info and there are two problems:

1. When the user hits the back button, the cc details remain in the fields as they were entered.

2. When a user types a number into the cc field, the browser shows all of the numbers that have been entered into that field.

How can I stop these things?

 Cheers, WT.
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