Hey Ger Vang,
I suggest you to store the macro value into the inline javascript variable. Then you can reference that variable from the external file of yours (just make sure you reference that variable AFTER being assigned to).
More advanced js techniques may apply as method I described is not the best option for greater maintainability. However if don't plan on heavy complicated javascript single page architecture, this approach might be as good as any other.
In my very personal opinion, I would not event recommend macro-like replacements in the source code files (your external JS code) as it would have a severe impact on the code readability and cleanliness.
I hope that helps,
Pavel