...
. GoogleTagManager + Univarsal GAnalytics + ... dataLayer .
1) dataLayer GTM ( Rails application.html/haml):
<script>
dataLayer = [];
</script>
2), :
<script>
dataLayer.push({
"&uid": "#{YOUR-BACKEND-USER-ID}"
});
</script>
3) GTM
(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 =
'//www.googletagmanager.com/gtm.js?id=' + i + dl;
f.parentNode.insertBefore(j, f);
})(window, document, 'script', 'dataLayer', 'GTM-XXXXX');
4) "uid" . Layer Variable Name & uid
5) ( ). > : & uid | : {{uid}}
6) Google Analytics USER-ID. admin > account > property > tracking info > USER-ID CREATE