The Web Client uses a third-party library around the HTML post.message method that is used to send secure events. This library, which is called postRobot (version 8) from PayPal, is used to overcome the many limitations of using post.message.
The extensibility application can send and receive the following communication events:
Init - This event includes the following contextual information:
The client URL, which includes the full domain and pathname.
The method and information about all of its parameters.
Object OBIDs of any selected contextural objects.
The configurations the user has currently set.
loading - This event lets you turn the loading indicator on or off.
actionMenu - This event lets you open or close the Actions menu. It can include data as a single object or as multiple objects.
Token information ("getToken) - This event allows the extensibility application to retrieve the access token so it can make http requests.