As the photo - Variable 'n' has already been declared.

I've tried clearing my cache, as well as using a new user profile with no extensions, but it doesn't work.

Might be useful to know so it can be fixed before more people are using Chrome (If it's SO's fault of course!)

  • 11
    This probably won't be addressed; pre-release versions aren't supported and the developers usually ignore issues with them.
    – Jeremy
    Jan 13, 2012 at 16:55
  • 3
    Hmm, I'm unable to reproduce this in Chrome 18 (although the error suggests a browser-independent issue anyway).
    – Tim Stone
    Jan 13, 2012 at 17:09
  • 4
    -1 For making me think my Chrome was horribly out of date...
    – yannis
    Jan 13, 2012 at 17:18
  • I'm on the beta release and I too was like "18 WTF BBQ"
    – Ben Brocka
    Jan 13, 2012 at 20:24
  • Chrome 18? Get you. @ZaphodBeeblebrox yeh I checked mine too
    – Chris S
    Jan 13, 2012 at 20:27
  • I am also facing this problem
    – user
    Feb 2, 2012 at 17:31
  • Yeah, I'm having problems every other day it seems. Feb 2, 2012 at 19:19

3 Answers 3


This is only a problem when the "Experimental Javascript" flag is enabled. I've disabled it in chrome://flags, and now everything is fine again:

It should be noted that this flag also causes problems with Google's own Google Maps - I would disable it unless it's really needed.


While pre-release browsers really aren't supported, re-declared variables are a bug either way. I suppose Chrome's strict mode is getting stricter. I have removed (next build) a couple of re-declarations; none of them was called n in the current minified version, though (they're j and q). So I'll call this .

  • This seems an odd one doesn't it. I've tried refreshing/new profile etc etc but still no dice. Looking at the full.js, the minified version does have var n= in it 28 times, so perhaps the minification is a little lax on something that Chrome's strict mode chokes on. If it starts working again I'll reply here, as at this point I'd assume it's a Chrome bug. Jan 13, 2012 at 19:36
  • FYI, the change has been built about 1.5 hours ago.
    – balpha StaffMod
    Jan 13, 2012 at 19:55
  • Working again (as of 16th Jan) - this can be marked as fixed. Jan 16, 2012 at 9:17
  • I'm still experiencing this error on Chrome 18 for Mac OS X. It's a particularly irritating bug in that it prevents all Javascript, renderinging buttons for comments, voting, etc useless. I've had to switch to Firefox to post this. Jan 20, 2012 at 12:49
  • 3
    Upon experimentation, I've discovered that this is only a problem when the "Experimental Javascript" flag is enabled. I've disabled it, and now everything is fine again. Jan 21, 2012 at 16:14
  • I am still facing this problem
    – user
    Feb 2, 2012 at 17:32
  • @LiamNewmarch: You are right. Problem lies in "Experimental Javascript" flag
    – user
    Feb 2, 2012 at 17:34
  • 1
    The n still/again seems to be bothering some: JavaScript error "Variable 'n' has already been declared" prevents UI interaction.
    – Arjan
    Feb 3, 2012 at 8:35
  • 1
    @Arjan: Since this isn't causing issues in any supported browser, I'm not really worried. If someone tells me where exactly this error is happening, I'll fix it; otherwise, it'll have to wait until this appears in the Chrome release version so I can hunt it down myself.
    – balpha StaffMod
    Feb 3, 2012 at 10:53

Pre-release browsers aren't supported (as Jeremy Banks already noted).

However, balpha did recently make changes to full.js, where this error appears to be occurring. It may be related.

  • 10
    I make changes to that file all the time :)
    – balpha StaffMod
    Jan 13, 2012 at 17:14

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