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

Incredible Demos

  • By
    Detect Vendor Prefix with JavaScript

    Regardless of our position on vendor prefixes, we have to live with them and occasionally use them to make things work.  These prefixes can be used in two formats:  the CSS format (-moz-, as in -moz-element) and the JS format (navigator.mozApps).  The awesome X-Tag project has...

  • By
    Form Element AJAX Spinner Attachment Using MooTools

    Many times you'll see a form dynamically change available values based on the value of a form field. For example, a "State" field will change based on which Country a user selects. What annoys me about these forms is that they'll often do an...

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!