- From: Sid Stamm <sid@mozilla.com>
- Date: Wed, 21 Dec 2011 11:06:04 -0800 (PST)
- To: Justin Lebar <jlebar@mozilla.com>
- Cc: public-tracking@w3.org, Jonas Sicking <jonas@sicking.cc>
Forwarding this to public-tracking where the DNT stuff is being discussed. -Sid ----- Original Message ----- > From: "Justin Lebar" <jlebar@mozilla.com> > To: public-privacy@w3.org, "Sid Stamm" <sid@mozilla.com>, "Jonas Sicking" <jonas@sicking.cc> > Sent: Wednesday, December 21, 2011 11:00:51 AM > Subject: Value returned by navigator.doNotTrack > 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 19:06:32 UTC