TC: conditionally executing window.alert()

I am using FF to develop a TC 12.53 script. I am using some Eval JS code window.alert(...); statements to debug the script and inspect parameter values, as in:

But when I execute that script under vuGen the script hangs on the first of these statements, without the popup alert dialog being presented so it can be manually dismissed. (and even if the dialog is presented under vuGen, I can see the obvious problem attempting to run the script under a Controller).

So is there anyway to condition these Steps (surrounded by some type of IF(...) statement) so that they are only executed when I am in Develop Script mode? Or do I have to manually disable all of these Steps before exiting Develop Script mode?

-Thanks, Terry