HTML5 Web Storage Cleared when Browser Clear Cache?

Is HTML5 Web Storage cleared when the browser clears its cache? If it does, many people like me may lose 开发者_高级运维data if they accidentally clear cache? or like in this comment ...

Since HTML5 local storage is kept separate from js cookies (like Silverlight, Gears, Flash), it opens up a world of 3rd party privacy issues for HTML5 as these objects will likely NOT get deleted with a clear cache or delete temporary data

... where web storage is not cleared, but leads to privacy issues?

To quote the Mozilla Developer Center:

DOM Storage can be cleared via "Tools -> Clear Recent History -> Cookies" when Time range is "Everything" (via nsICookieManager::removeAll)

Note that Flash cookies, OTOH, are quite a bit harder to remove.