After updated the top menu bar, I always can't leave comment and get this JS error.
I am using Chrome 31.0.1650.63 m. But there is no error when I am using incognito mode.
PS: tried to clear all related cache, cookie.
Meta Stack Exchange is a question and answer site for meta-discussion of the Stack Exchange family of Q&A websites. It only takes a minute to sign up.Sign up to join this community
You have something loading jQuery on it's own, nuking our copy with methods added. You'll need to fix or remove whatever user script or other content your browser is injecting that interferes with the page.
Unless this user script is scoped to just our sites (in that case, stop including jQuery - we already do that) you'll likely get problems like this on any major website using jQuery.