Author here. :) To the credit of the standards bodies, I think speccing a database presents a totally different set of challenges than with the typical browser

Author here. :) To the credit of the standards bodies, I think speccing a database presents a totally different set of challenges than with the typical browser APIs. The fact that it took them three tries to get something everybody liked (LocalStorage -> WebSQL -> IndexedDB) is a real testament to that. Also to the browser vendors' credit, the bar is way higher when you're implementing something like IndexedDB than the typical CSS/DOM stuff. A bug in CSS/DOM means the page looks weird; a bug in IndexedDB means your users lose data. And when you fix the bugs, you still have to migrate the existing user data, because it's sitting out there on people's hard drives. A page refresh isn't enough. So given how insanely ambitious it is to have four independent implementations of the same database (Chromium/Firefox/IE/WebKit), I'd say the browser vendors have done a pretty great job. Firefox and Chrome in particular have shown it's possible to get it right with separate implementations; as of Chrome 38, I don't see any functional difference between the two.