1. Dart
2. dart:html
3. Client
4. postMessage method

##### Client class

1. Properties
2. frameType
3. hashCode
4. id
5. runtimeType
6. type
7. url
8. Methods
9. noSuchMethod
10. postMessage
11. toString
12. Operators
13. operator ==

description

# postMessage method Null safety

void postMessage (

1. Object message,
2. [List<Object>? transfer]

)

## Implementation

    void postMessage(Object message, [List<Object>? transfer]) native;