Adblocking software like AdBlock Plus have become mainstream and now pose a significant threat to web businesses that are dependent on online advertisements. The problem is so severe that Google and Amazon are paying the writers of AdBlock Plus to whitelist their ads. This may be seen as some kind of extortion but with billions of dollars at stake, the advertising companies have chosen to take the more profitable route.

It is estimated that ~5% of website visitors are blocking ads (PDF report) and the situation could be far worse for websites that have a more tech-savvy audience. If you are curious to know how many people visiting your own site are blocking AdSense and other ads, here’s a little trick.

Track Adblock Users with Google Analytics

Open your website template and copy-paste the snippet below before the closing body. This code will detect the presence of adblocking software on the visitor’s browser and, if found, an event gets logged into your Google Analytics account.

<script>

  window.onload = function() {

    // Delay to allow the async Google Ads to load
    setTimeout(function() {

      // Get the first AdSense ad unit on the page
      var ad = document.querySelector("ins.adsbygoogle");

      // If the ads are not loaded, track the event
      if (ad && ad.innerHTML.replace(/\s/g, "").length == 0) {

        if (typeof ga !== 'undefined') {

            // Log an event in Universal Analytics
            // but without affecting overall bounce rate
            ga('send', 'event', 'Adblock', 'Yes', {'nonInteraction': 1});

        } else if (typeof _gaq !== 'undefined') {

            // Log a non-interactive event in old Google Analytics
            _gaq.push(['_trackEvent', 'Adblock', 'Yes', undefined, undefined, true]);

        }
      }
    }, 2000); // Run ad block detection 2 seconds after page load
  };

</script>

The snippet works for both Universal Analytics and the older version of Google Analytics tracker that used the _gaq object. As a web publisher, your only option is to serve alternate content to AdBlock users so the visitors at least see some content in place of the ads.

One big caveat though - it will fail if the ad blocking extension installed on the visitor’s computer has blocked Google Analytics as well. Some of the popular choices like μBlock, NoScript and Ghostery do block Google Analytics so the approach won’t work and you may have to build your own in-house solution - like downloading an image hosted on your own server and then counting the hits to that image through the Apache server logs.

Also see: Use Google Analytics without JavaScript