Fraid not. Short answer is that all the verification is done clientside (which is NOT secure) so the server only knows that someone wants to see the file; it doesn't know whether it's a browser or a user doing it.
Long answer is that it *is* possible to check for the usual signs of a browser, and deny reading of the file if they're not there, but there are pleanty of ways round this, it's fiddley, and doesn't work with everything.
What information are you trying to protect in the JS file? Just the code to do something, or passwords/sensitive data?
