Array comprehension example won't work

Do you see anything wrong with this range function?

https://developer.mozilla.org/en/new_in_javascript_1.7#Array_comprehensions_%28Merge_into_Array_comprehensions%29

This is so fucking. I don't know what the fuck to do about programming "NEW JS" for browser clients because they're all fucking different. What the fuck would you have me do, you stupid browser faggots? Exactly when should I start using let, huh? Never, because people will still be using IE7 five years from now? Fuck this.