To try this example, open it in Chrome (version 42+) and try to start filling the fields. Chrome will suggest you 'auto fill' data from what it got so far.
Wallet Integration
If you got
Google Wallet
with you credit card data, even better! Go to the
'Payment' section
and start to fill the data. Chrome will offer you to pre-fill it with the current credit card's information wallet got on file.
(!) The current spec:
html.spec.whatwg.org/multipage/forms.html