Update: The debugger is running; I missed it at first because it opened into a new window and my immediate reaction to popups kicked in.
The debugger is reporting an error when I reference the function log or the variable companyhome, both of which are part of the API rather than core EMCAScript.
Is there a way to make the debugger aware of API functions, objects, and variables?
If you're in the context of your web script when you're using the debugger, then all those API variables should be available. Personally, I do this by hitting the "Break" button and then accessing my script.
I think I was not using the debugger in the intended way; I started up and didn't know what to press to start stepping through it (the 'Step into' button did not look active), and loaded and ran the script 'bare'.