Google Tag Management System

What is tag

Tag is a JS code snippet inserted into a web page to track user event. Meta pixel and Goggle ad are some example of tags

What problem we have if we use multiple tags in a web page

• Will need to add a code snippet for every tag. For example, if we use five track tools from ten different company, we need to add 10 extra code snippets in different pages
• If we want to change some thing such as account id, we need to go to every page to modify them

Google Tag Management System

Tag management system likes an container. You set up and update tags in the tag management system, and you only need one extra code snippent in a web page no matter how many tags you want to use. Google Tag Management System is one of these systems.

Use Google Tag Management System, and you can

• Set up tags
• Set up event rules

gtag.js

gtag.js is the JavaScript framework that is used to add Google tags directly to web pages. It can not add third party tags.

Here what we need is a tag id

// Google tag (gtag.js)
<script async src="https://www.googletagmanager.com/gtag/js?id=TAG_ID"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments)};
  gtag('js', new Date());

  gtag('config', 'TAG_ID');
</script>

The Google tag lets you send data from your website to linked Google product destinations. By now only Google Ads accounts and web data streams in GA4 properties can be destinations.

You can use a single Google tag across your entire website and connect the tag ID to multiple destinations.