Before I put google analytics, adwords, or other third party scripts on my sites I can respect the DNT headers a user has set. Here’s how I can do it with Google Analytics:
<script>
if (window.navigator.doNotTrack !== '1') {
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-xxxxxxx-5', 'auto');
ga('send', 'pageview');
}
</script>
In the above snippet I check if the user has enabled DNT. If they haven’t set the header or they have turned it off the script will run. Checking for window.navigator.doNotTrack !== '1' ensures that the user purposely set the header.