Is there something like firebug for actionscript?

I really like MonsterDebugger, easy to use, for Flash, Flex, AIR. Check it out here - http://www.monsterdebugger.com/

If you're using Flash, try pressing Control-Shift-Enter to launch swf. This will open the debugger (click the green arrow to start executing the code).

If you are using Flex Builder, you have a complete debugger .

In any environment, you can set breakpoints, these are the points you can specify in your code where code execution needs to be stopped so that you can investigate what is going on.

You can use the class LocalConnection

to communicate with other swf. I use this concept to view traced messages in a browser.

• Create a SWF debugger that accepts local connection requests and displays all incoming text in a text area.
• Write a Debug class with a static write method that sends incoming text to the debugger over a local connection (and optionally monitors the message).
• Include the Debug class in your application and replace all trace calls with Debug.write
• (Optional) Write fancy writeError writeWarning methods that displays important messages in different colors.
• Start the swf debugger in your browser.

I have code for these, but SO allows file uploads? The code dragged on a bit when I did a search and highlighted the console with a regex.

If you are using command line tools (not flex builder or flashIDE), you can use the command line debugger, FDB. You can find it in flexSDK / bin folder. There is a lot of documentation for this (rather frustrating) tool.