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Re: Value returned by navigator.doNotTrack

From: Justin Lebar <jlebar@mozilla.com>
Date: Wed, 21 Dec 2011 16:00:19 -0500
Message-ID: <CAFWcpZ5gGjrowhJ_BMRX5HxU0S5yvvXB+4RuaFYp7y-RxymLAA@mail.gmail.com>
To: Richard Barnes <richard.barnes@gmail.com>
Cc: public-privacy@w3.org, Sid Stamm <sid@mozilla.com>, Jonas Sicking <jonas@sicking.cc>
> If you want to make that fail, then maybe you should make it a string.

Yes, that's precisely my proposal with "yes", "no", and "unspecified".
 I prefer this to an enum.

On Wed, Dec 21, 2011 at 3:57 PM, Richard Barnes
<richard.barnes@gmail.com> wrote:
> It seems wrong to be conditioning an if statement on a ternary value
> anyway.  If you want to make that fail, then maybe you should make it
> a string.  You could use the values used informally in the draft spec,
> "OPT-IN", "OPT-OUT", and "NO-EXPRESSED-PREFERENCE" [1].  Maybe via an
> enum.
>
> if (navigator.doNotTrack == DNT.optIn) { /* track */ }
> else if (navigator.doNotTrack == DNT.optOut) { /* don't track */ }
> else if (navigator.doNotTrack == DNT.noExpressedPreference) { /*
> probably track anyway */ }
> else { /* there is no else */ }
>
> --Richard
>
> [1] <http://tools.ietf.org/html/draft-mayer-do-not-track-00#section-6.1>
>
>
>
> On Wed, Dec 21, 2011 at 3:47 PM, Justin Lebar <jlebar@mozilla.com> wrote:
>> On Wed, Dec 21, 2011 at 3:28 PM, Richard Barnes
>> <richard.barnes@gmail.com> wrote:
>>> How about just using NaN?  That would be consistent with just calling
>>> parseInt() on the content of the header ("0", "1", or "").
>>
>> If we made navigator.doNotTrack a number (0, 1, NaN), then
>>
>>  if (navigator.doNotTrack)
>>
>> would work correctly.  But then the negation,
>>
>>  if (!navigator.doNotTrack)
>>
>> is not right.  :)
>>
>>> On Wed, Dec 21, 2011 at 2:00 PM, Justin Lebar <jlebar@mozilla.com> wrote:
>>>> In Firefox, we implemented navigator.doNotTrack to return either
>>>>
>>>>  "unspecified", if the user has not opted in to DNT, or
>>>>  "yes", if the user has opted in to DNT.
>>>>
>>>> The proposed DNT spec has us return "1" if the user has opted in to
>>>> DNT and doesn't seem to specify what we should return otherwise.
>>>>
>>>> I propose the spec be modified to explicitly state what UAs should
>>>> return if the user has not opted in to DNT, and to use unspecified/yes
>>>> instead of ??/1.
>>>>
>>>> DNT is a tri-state, not a boolean.  The DNT http header may be 1, 0,
>>>> or not present.  0 indicates that the user has explicitly opted in to
>>>> tracking.  Although Firefox doesn't support this option at the moment,
>>>> we'd like to spec DNT in such a way as to allow users to explicitly
>>>> opt in to tracking.  We propose that navigator.doNotTrack == "no"
>>>> correspond to DNT: 0.
>>>>
>>>> It's confusing that navigator.doNotTrack's value doesn't correspond to
>>>> the value of the HTTP header, but we did this because we wanted to
>>>> protect against buggy JS which assumes navigator.doNotTrack is a
>>>> boolean.  If we were to use navigator.doNotTrack == '' for users who
>>>> have neither oped in nor out of DNT, then sites could do |if
>>>> (navigator.doNotTrack) { // don't track me }|.  This would make it
>>>> difficult for us to introduce navigator.doNotTrack = "no" in the
>>>> future, because "no" resolves to the boolean |true|.
>>>>
>>>> I've filed a webkit bug on this issue [1].
>>>>
>>>> [1] https://bugs.webkit.org/show_bug.cgi?id=75008
>>>>
Received on Wednesday, 21 December 2011 21:01:11 GMT

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