Add GTM (fixes #7)

2017-11-08 22:58:08 +01:00 · 2017-11-08 22:58:08 +01:00 · d0da745aa1
--- a/index.html
+++ b/index.html
@ -8,6 +8,26 @@

    <link rel="stylesheet" href="style.css">
    <link rel="stylesheet" href="https://fonts.googleapis.com/css?family=Fira+Sans|Zilla+Slab">
+
+    <!-- Google Tag Manager -->
+    <script src="js/dnt-helper.js"></script>
+    <script>
+      if (!_dntEnabled()) {
+        (function(w, d, s, l, i) {
+            w[l] = w[l] || [];
+            w[l].push({
+                'gtm.start': new Date().getTime(),
+                event: 'gtm.js'
+            });
+            var f = d.getElementsByTagName(s)[0],
+                j = d.createElement(s),
+                dl = l != 'dataLayer' ? '&l=' + l : '';
+            j.async = true;
+            j.src = 'https://www.googletagmanager.com/gtm.js?id=' + i + dl;
+            f.parentNode.insertBefore(j, f);
+        })(window, document, 'script', 'dataLayer', 'GTM-K59SSLL');
+      }
+    </script>
  </head>

  <body>
--- a/js/dnt-helper.js
+++ b/js/dnt-helper.js
@ -0,0 +1,48 @@
+/**
+ * The MIT License (MIT)
+ * Copyright (c) 2015 Schalk Neethling
+ *
+ * Returns true or false based on whether doNotTack is enabled. It also takes into account the
+ * anomalies, such as !bugzilla 887703, which effect versions of Fx 31 and lower. It also handles
+ * IE versions on Windows 7, 8 and 8.1, where the DNT implementation does not honor the spec.
+ * @see https://bugzilla.mozilla.org/show_bug.cgi?id=1217896 for more details
+ * @params {string} [dnt] - An optional mock doNotTrack string to ease unit testing.
+ * @params {string} [userAgent] - An optional mock userAgent string to ease unit testing.
+ * @returns {boolean} true if enabled else false
+ */
+function _dntEnabled(dnt, userAgent) {
+  'use strict';
+
+  // for old version of IE we need to use the msDoNotTrack property of navigator
+  // on newer versions, and newer platforms, this is doNotTrack but, on the window object
+  // Safari also exposes the property on the window object.
+  var dntStatus = dnt || navigator.doNotTrack || window.doNotTrack || navigator.msDoNotTrack;
+  var ua = userAgent || navigator.userAgent;
+
+  // List of Windows versions known to not implement DNT according to the standard.
+  var anomalousWinVersions = ['Windows NT 6.1', 'Windows NT 6.2', 'Windows NT 6.3'];
+
+  var fxMatch = ua.match(/Firefox\/(\d+)/);
+  var ieRegEx = /MSIE|Trident/i;
+  var isIE = ieRegEx.test(ua);
+  // Matches from Windows up to the first occurance of ; un-greedily
+  // http://www.regexr.com/3c2el
+  var platform = ua.match(/Windows.+?(?=;)/g);
+
+  // With old versions of IE, DNT did not exist so we simply return false;
+  if (isIE && typeof Array.prototype.indexOf !== 'function') {
+      return false;
+  } else if (fxMatch && parseInt(fxMatch[1], 10) < 32) {
+      // Can't say for sure if it is 1 or 0, due to Fx bug 887703
+      dntStatus = 'Unspecified';
+  } else if (isIE && platform && anomalousWinVersions.indexOf(platform.toString()) !== -1) {
+      // default is on, which does not honor the specification
+      dntStatus = 'Unspecified';
+  } else {
+      // sets dntStatus to Disabled or Enabled based on the value returned by the browser.
+      // If dntStatus is undefined, it will be set to Unspecified
+      dntStatus = { '0': 'Disabled', '1': 'Enabled' }[dntStatus] || 'Unspecified';
+  }
+
+  return dntStatus === 'Enabled' ? true : false;
+}