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Re: Value returned by navigator.doNotTrack

From: Richard Barnes <richard.barnes@gmail.com>
Date: Wed, 21 Dec 2011 15:28:18 -0500
Message-ID: <CACB24Ms0PeQFwuJCyPmCkVDjcs6sT7jHh8qZHFwwhN5VQ4SWHw@mail.gmail.com>
To: Justin Lebar <jlebar@mozilla.com>
Cc: public-privacy@w3.org, Sid Stamm <sid@mozilla.com>, Jonas Sicking <jonas@sicking.cc>
How about just using NaN?  That would be consistent with just calling
parseInt() on the content of the header ("0", "1", or "").

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 20:28:46 UTC

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