Using the ExternalInterface class
Communication between ActionScript and the container application can take one of two forms: either ActionScript can call code (such as a JavaScript function) defined in the container, or code in the container can call an ActionScript function that has been designated as being callable. In either case, information can be sent to the code being called, and results can be returned to the code making the call.
To facilitate this communication, the ExternalInterface class includes two static properties and two static methods. These properties and methods are used to obtain information about the external interface connection, to execute code in the container from ActionScript, and to make ActionScript functions available to be called by the container.