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 to Create a RetroPie on Raspberry Pi – Graphical Guide

    Today we get to play amazing games on our super powered game consoles, PCs, VR headsets, and even mobile devices.  While I enjoy playing new games these days, I do long for the retro gaming systems I had when I was a kid: the original Nintendo...

  • By
    Welcome to My New Office

    My first professional web development was at a small print shop where I sat in a windowless cubical all day. I suffered that boxed in environment for almost five years before I was able to find a remote job where I worked from home. The first...

Incredible Demos

  • By
    JavaScript Copy to Clipboard

    "Copy to clipboard" functionality is something we all use dozens of times daily but the client side API around it has always been lacking; some older APIs and browser implementations required a scary "are you sure?"-style dialog before the content would be copied to clipboard -- not great for...

  • By
    Skype-Style Buttons Using MooTools

    A few weeks back, jQuery expert Janko Jovanovic dropped a sweet tutorial showing you how to create a Skype-like button using jQuery. I was impressed by Janko's article so I decided to port the effect to MooTools. The XHTML This is the exact code provided by...

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!