To prevent messages from being delivered before the destination is ready, client.postMessage() does not dispatch the message until one of the following has occurred on the destination: - 'DOMContentLoaded' event is fired. - onmessage is set. - startMessages() is called.



Editor's draft

Status in Chromium


Enabled by default (tracking bug) in:

  • Chrome for desktop release 74
  • Chrome for Android release 74
  • Android WebView release 74

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

  • Shipped/Shipping
  • No signal
  • No signal
  • No signals


Last updated on 2020-11-09