W3C home > Mailing lists > Public > public-web-perf@w3.org > May 2011

Re: [Page Visibility] Spec -- privacy concern

From: Adam Shannon <adam@ashannon.us>
Date: Fri, 13 May 2011 19:02:34 -0500
Message-ID: <BANLkTikLZD94A8YvuhWb9b5L=EUtP-qAOw@mail.gmail.com>
To: Kyle Simpson <getify@gmail.com>
Cc: public-web-perf@w3.org
First, I think it's well known that prompting users for permission (or
any purpose) doesn't actually work. Users tend to just "want" the page
to work, and if a dialog is in their way they don't care.

Secondly, can't a page already figure out how long you've been on the page?

// Something like this
(function () {
    window.mySecretCode.timestarted = +new Date();

window.onunload = function () {
    var xhr = new XMLHttpRequest();
         xhr.open('GET', '...' + '?timespent=' + (+new Date() -
window.mySecretCode.timestarted), false);

I think it is a huge privacy concern and I like the idea that this
namespace could only be seen/used by  same-origin scripts.

On Fri, May 13, 2011 at 18:50, Kyle Simpson <getify@gmail.com> wrote:
> One major privacy concern I (and others I chatted with on Mozilla's
> #developers IRC) have is that third-party scripts (like ad providers, etc)
> would be able to monitor this type of data (page visibility) and gain
> valuable (to them!) information which a user might not want them to have,
> such as how long I stay viewing a page, etc.
> I think this is possibly an intractable concern, unless there's some way to
> enforce that only scripts which originated from the same exact domain as the
> page could access such data, not all JS from any location.
> Alternatively (and possibly more usefully, for the user education/knowledge
> perspective), maybe this feature could be an opt-in prompt similar to
> geolocation... so that user-agents have to ask the user for permission (and
> allow it to be a rememberable preference) before giving that information to
> the page (of course, only if the page tries to access it).
> The prompt could be something like: "The site you are viewing wants to
> monitor some aspects of how you use the browser window to view this page,
> possibly for optimizing the performance while the page is inactive in your
> browser."
> --Kyle

Adam Shannon
Web Developer
University of Northern Iowa
Sophomore -- Computer Science B.S.
Received on Saturday, 14 May 2011 00:03:22 UTC

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