How to use ExternalInterface to integrate AS3 with JavaScript

Here's a quick snippet of code for integrating your SWFs with JavaScript, using ExternalInterface:

Actionscript:

import flash.external.ExternalInterface;
// Calling a JavaScript function from AS3 (with optional parameters)
if (ExternalInterface.available) ExternalInterface.call("javascriptFunction", param1, param2);
// Implementing a JavaScript callback in AS3 (flashFunction is called when JavaScript calls javascriptFunction)
if (ExternalInterface.available) ExternalInterface.addCallback("javascriptFunction", flashFunction);