It looks like Firefox is going to take a different route than other (Webkit-based) browsers, by adopting the [“Indexed Database API”](http://dev.w3.org/2006/webapi/WebSimpleDB/), rather than the [“Web SQL API”](http://dev.w3.org/html5/webdatabase/) for storage of local data in the browser, that are used by e.g. [persistence.js](http://github.com/zefhemel/persistencejs). The Indexed Database API is a type of NoSQL database. You can store JSON-formatted documents in it and retrieve them. It does not support SQL. In a way this makes sense, as the proposed Web SQL standard was essentially dictating that SQLite should be provided by the browsers, which is not a great way of creating a standard — and would Internet Explorer ever include SQLite in its browser? Not likely.