Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.
Non-standard: This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.
Secure context: This feature is available only in secure contexts (HTTPS), in some or all supporting browsers.
The MerchantValidationEvent property validationURL is a read-only string value providing the URL from which to fetch the payment handler-specific data needed to validate the merchant.
This data should be passed into the complete() method to let the user agent complete the transaction.
