Khan/khan-exercises — comment on commit 5226cf92ba6766843daf0279f1c4cbe91448f3ca
File:  line 0
By beneater:

Perhaps not. But assigning to `clock` rather than `var clock` was also causing problems since IE helpfully creates a global object named `clock` because there's a div with that id.

So maybe that was the only reason it was failing in production and the comma/semicolon stuff just popped up when I was debugging.