Currently any attempt to call window.postMessage on window from another domain will produce console error "Unsafe JavaScript attempt to access frame with URL...". Since postMessage is designed for cross domain communication it should not write error messages about cross-domain access.
Is this accurate? I don't see any messages in console when running regression tests, such as http://127.0.0.1:8000/security/postMessage/delivery-order.html.
(In reply to comment #1) > Is this accurate? I don't see any messages in console when running regression > tests, such as http://127.0.0.1:8000/security/postMessage/delivery-order.html. It turned to be Web Inspector issue. It's not postMessage that causes that exception. I'll close this bug and file another one with accurate description.