1. @DomName('Window.postMessage')
  2. @DocsEditable()
void postMessage(Object message, String targetOrigin, [ List<MessagePort> transfer ])

Sends a cross-origin message.

Other resources

Source 

@DomName('Window.postMessage')
@DocsEditable()
void postMessage(Object message, String targetOrigin,
        [List<MessagePort> transfer]) =>
    _blink.BlinkWindow.instance.postMessage_Callback_3_(
        this,
        convertDartToNative_SerializedScriptValue(message),
        targetOrigin,
        transfer);