ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Using the external API
Exposing ActionScript methods to JavaScript
Flash Player 9 and later, Adobe AIR 1.0 and later
As the previous example showed, once the code determines that the browser is ready, the setupCallbacks() method
is called. This method prepares ActionScript to receive calls from JavaScript, as shown here:
private function setupCallbacks():void
{
// Register the SWF client functions with the container
ExternalInterface.addCallback("newMessage", newMessage);
ExternalInterface.addCallback("getStatus", getStatus);
// Notify the container that the SWF is ready to be called.
ExternalInterface.call("setSWFIsReady");
}
The setCallBacks() method finishes the task of preparing for communication with the container by calling
ExternalInterface.addCallback() to register the two methods that will be available to be called from JavaScript.
In this code, the first parameter—the name by which the method is known to JavaScript ("newMessage" and
"getStatus")—is the same as the method’s name in ActionScript. (In this case, there was no benefit to using different
names, so the same name was reused for simplicity.) Finally, the ExternalInterface.call() method is used to call
the JavaScript function setSWFIsReady(), which notifies the container that the ActionScript functions have been
registered.
Communication from ActionScript to the browser
Flash Player 9 and later, Adobe AIR 1.0 and later
The Introvert IM application demonstrates a range of examples of calling JavaScript functions in the container page.
In the simplest case (an example from the setupCallbacks() method), the JavaScript function setSWFIsReady() is
called without passing any parameters or receiving a value in return:
ExternalInterface.call("setSWFIsReady");
In another example from the isContainerReady() method, ActionScript calls the isReady() function and receives
a Boolean value in response:
var result:Boolean = ExternalInterface.call("isReady");
You can also pass parameters to JavaScript functions using the external API. For instance, consider the IMManager
class’s sendMessage() method, which is called when the user is sending a new message to his or her “conversation
partner”:
public function sendMessage(message:String):void
{
ExternalInterface.call("newMessage", message);
}
Once again, ExternalInterface.call() is used to call the designated JavaScript function, notifying the browser of
the new message. In addition, the message itself is passed as an additional parameter to ExternalInterface.call(),
and consequently it is passed as a parameter to the JavaScript function newMessage().
Last updated 6/6/2012
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