"Console.log" with Photoshop Scripting - ExtendedScript Toolkit
Solution 1:
$.writeln() is what you're looking for. See the JavaScript Tools Guide (PDF) for details.
Solution 2:
I'm using ExtendScript Toolkit version 4.0, and using _print('foo') seems to do the trick.
Solution 3:
write("any message");
Is what works in XTools for Photoshop. I find that the Photoshop debugger crashes all the time in CS6 on Mac OSX.
You can find more about XTools here: http://ps-scripts.sourceforge.net/xtools.html.
It's fabulous!