[whatwg] Web Storage: apparent contradiction in spec

[James Graham]

Adrian Sutton wrote:
> On 27/08/2009 15:47, "Maciej Stachowiak" <mjs at apple.com> wrote:
>> - Cached for convenience - discarding this will affect performance but not
>> functionality.
>> - Useful for offline use - discarding this will prevent some data from being
>> accessed when offline.
>> - Critical for offline use - discarding this will prevent the app storing this
>> data from working offline at all.
>> - Critical user data - discarding this will lead to permanent user data loss.
>>
> The only catch being that if the web app decides this for itself, a
> malicious script or tracking cookie will be marked as critical user data
> when in fact the user would disagree.
> 
> On the plus side, it would mean a browser could default to not allowing
> storage in the critical user data by default and then let users whitelist
> just the sites they want.  This could be through an evil dialog, or just a
> less intrusive indicator somewhere ­ the website itself would be able to
> detect that it couldn¹t save and warn the user in whatever way is most
> appropriate.

I don't fancy having to explain to my Mum that she has to go through 
some complex (to her) sequence of operations to see if a site is storing 
her important data somewhere where it might be deleted or in some secure 
area. Nor do I fancy explaining the procedure for changing between one 
and the other. I don't really see how the site could help either. I 
guess it might be possible for it to put up a "your data is stored in a 
non-persistent way" message, but instructions to change to persistent 
storage would have to be per-browser and possibly per browser version; 
no good for the people who don't know the difference between "the 
browser", "the internet" and "google".

I can't imagine how to make this simple enough for end users without all 
data being persistent by default. Even then, knowing how to clear out 
data once the quota is hit is likely to be difficult and confusing.