Flash CS3 Documentation

Learning ActionScript 2.0 in Adobe Flash > Working with External Data > About the External API

About the External API

The ExternalInterface class is also called the External API, which is a new subsystem that lets you easily communicate from ActionScript and the Flash Player container to an HTML page with JavaScript or to a desktop application that embeds Flash Player.

The ExternalInterface class is available only under the following circumstances:

• In all supported versions of Internet Explorer for Windows (5.0 and later).
• In an embedded custom ActiveX container, such as a desktop application embedding the Flash Player ActiveX control.
• In any browser that supports the NPRuntime interface (which currently includes the following browsers:
  • Firefox 1.0 and later
  • Mozilla 1.7.5 and later
  • Netscape 8.0 and later
  • Safari 1.3 and later.

In all other situations, the ExternalInterface.available property returns false.

From ActionScript, you can call a JavaScript function on the HTML page. The External API offers the following improved functionality compared with fscommand():

• You can use any JavaScript function, not only the functions that you can use with fscommand function.
• You can pass any number of arguments, with any names; you aren't limited to passing a command and arguments.
• You can pass various data types (such as Boolean, Number, and String); you are no longer limited to String parameters.
• You can now receive the value of a call, and that value returns immediately to ActionScript (as the return value of the call you make).

You can call an ActionScript function from JavaScript on an HTML page. For more information, see ExternalInterface (flash.external.ExternalInterface). For more information on local file security, see About local file security and Flash Player.

The following sections contain examples that use the External API:

• Creating interaction with the External API
• Controlling Flash Video with the External API

Flash CS3