Intent to Implement: Window postMessage with options

[Dave Tapuska]

Contact emails dtap...@chromium.org Spec

https://github.com/whatwg/html/pull/3800 https://github.com/dtapuska/useractivation Summary Add a new Window.postMessage override that takes a dictionary as a 3rd argument. In order to add additional arguments to postMessage a dictionary should be allowed to be passed in, this provides for maximum flexibility. It also aligns the other types of post message to the following pattern (message, transferrables, options)

Motivation We'd like to be able to optionally specify if an iframe can propagate it's user activation information to the receiver of the postMessage. In order to do this we feel we need to add an argument to postMessage. Since postMessage doesn't take a dictionary this is a stepping stone in doing that.

Interoperability risk Firefox: No public signals Edge: No public signals Safari: No public signals Web developers: No signals Compatibility risk Low. Detecting presence of the new API is easy by checking the length of the function. Ongoing technical constraints None

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, Chrome OS, Android, and Android WebView)? Yes or no. Yes OWP launch tracking bug https://crbug.com/861735 Link to entry on the Chrome Platform Status https://www.chromestatus.com/features/5548196159815680 Requesting approval to ship?

No