FlashFirebug

FlashFirebug (now Flash Debugger) gives you the ability to debug any AS3 Flash on the web. Inspect the DisplayList, change properties on the fly and see the warnings, errors and traces directly in the extension. Use the inspector to hone in on elements, transform objects on the fly and use the console to run AS3 commands.

Console

FlashFirebug now allows you to run AS3 code inside any SWF file at run-time. FlashFirebug console supports most AS3 syntax including function calls, method invocations, control structures, object instantiation and much more. For advanced developers, you can now upload an SWF and inject it within the target SWF for advanced AS3 capabilities that are not present within the console.

Run AS3 code and use the printf function to view output inside the console.