Disable Google Analytics tracking codes if DNT is set.

load_ga_tracking_code_conditionally.html

<!-- Global site tag (gtag.js) - Google Analytics -->
<script>
    var dnt = (navigator.doNotTrack || window.doNotTrack || navigator.msDoNotTrack);
    var doNotTrack = (dnt == "1" || dnt == "yes");
    if (!doNotTrack) {
        (function () {
            var ga = document.createElement('script');
            ga.type = 'text/javascript';
            ga.async = true;
            ga.src = 'https://www.googletagmanager.com/gtag/js?id=UA-ADD-YOUR-ID';
            var s = document.getElementsByTagName('script')[0];
            s.parentNode.insertBefore(ga, s);
        })();
        window.dataLayer = window.dataLayer || [];
        function gtag() {
            dataLayer.push(arguments);
        }
        gtag('js', new Date());
        gtag('config', 'UA-ADD-YOUR-ID');
    }else{
        console.debug("Respecting Do-Not-Track, not loading analytics.");
    }
</script>