Detect “Do Not Track” with JavaScript

By  on  

Do Not Track is an excellent idea.  The DNT website describes it best:

Do Not Track is a technology and policy proposal that enables users to opt out of tracking by websites they do not visit, including analytics services, advertising networks, and social platforms. At present few of these third parties offer a reliable tracking opt out, and tools for blocking them are neither user-friendly nor comprehensive. Much like the popular Do Not Call registry, Do Not Track provides users with a single, simple, persistent choice to opt out of third-party web tracking.

The preference is sent from the client to the server via a HTTP header but you can also get its value using JavaScript:

// "1" or "unspecified"
if(navigator.doNotTrack == 1) {
    // Do (or don't do) stuff.
}

If you wanted to be extreme about honoring your user's preference, you could use that to lazyload (or not) advertising, analytics, or other utilities. Probably a bit extreme but it's there for you to use!

Recent Features

  • By
    How I Stopped WordPress Comment Spam

    I love almost every part of being a tech blogger:  learning, preaching, bantering, researching.  The one part about blogging that I absolutely loathe:  dealing with SPAM comments.  For the past two years, my blog has registered 8,000+ SPAM comments per day.  PER DAY.  Bloating my database...

  • By
    CSS Animations Between Media Queries

    CSS animations are right up there with sliced bread. CSS animations are efficient because they can be hardware accelerated, they require no JavaScript overhead, and they are composed of very little CSS code. Quite often we add CSS transforms to elements via CSS during...

Incredible Demos

  • By
    MooTools, Mario, and Portal

    I'm a big fan of video games. I don't get much time to play them but I'll put down the MacBook Pro long enough to get a few games in. One of my favorites is Portal. For those who don't know, what's...

  • By
    MooTools Equal Heights Plugin:  Equalizer

    Keeping equal heights between elements within the same container can be hugely important for the sake of a pretty page. Unfortunately sometimes keeping columns the same height can't be done with CSS -- you need a little help from your JavaScript friends. Well...now you're...

Discussion

  1. Is the resulting value always a string or an integer except when unspecified (then it is a string), and are the values you stated the same cross-browser (especially the unspecified value)?

  2. Matt

    I really like how medium handles DNT.

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!