The onFocus( ) callback invokes the function registered against this event when the hosted field in the iFrame has gained focus.
PaymentSession.onFocus([<HostedFieldsRole>],function(selector))
PaymentSession.onFocus(['cardNumber', 'securityCode'], function(selector) { //handle focus event });
An array of field roles for the hosted fields where the event occurred. Valid array of field roles: ['cardNumber','securityCode']
The callback function invoked with the selector for the field whose proxy triggered the event.
None