That URL redirects me to http://worldclock.tofumatt.com/#/clock, but if I hit the "Back" button, I get to the URL you listed and there is no clock.

I have seen some invalidstateerrors on this for some folks. I'm looking into it, sorry! :-/

Isn't that because indexedDB isn't accessible in private browsing? Not sure what's wrong with Chrome though. It seems not to be complaining about invalid state or about anything.

edit: for Chromium the clock wasn't visible, fixing the height helps

    document.getElementsByTagName('section')[0].style.height = '100px';

I don't see anything either (chrome, osx)

It does seem to work with Firefox although I had a very hard time with the pull down widget for time zones.

Same on chrome. Puts my firefox in an infinite loop or something

Ditto

fails for me in private browsing mode because firefox can't remember history, works in normal mode