Writing this article is dangerous. Data Layer is two marketers short of becoming a buzz word. This occasion will be heralded by articles such as “Data Layer Is Dead”, “This Developer Implemented A Data Layer And You’ll Never Guess What Happened Next”, and other examples of the kind of content generation whose propagation should be prevented by military force. This is not one of those articles, I hope, but rather an honest look at what Data Layer is from a number of perspectives.
Rules are the cornerstone of Google Tag Manager. As with any critical element in a system, they are easy to get wrong. This tip is just a refresher on how GTM firing and blocking rules work.
Tip 3: Google Tag Manager rules in a nutshell So, let’s go through these points one-by-one.
Every tag requires a firing rule to work - this is a given. Without a firing rule, your tag will not be written in the document object, and it will never be executed.
Here’s a simple way to check what was the source of the visitor’s arrival to the current page. It’s done by utilizing the {{referrer}} macro, which comes out-of-the-box in any GTM setup.
Tip 2: Use {{referrer}} to see where the visitor came from You might want to also explore the Component Types and create new macros for {{referrer path}} and {{referrer host name}} for example:
By default, you see, the {{referrer}} macro returns the entire URL of the previous page.
I wanted to try something new (and, naturally, I’m running out of content ideas), so let me introduce the hashtag #gtmtips. I hope others contribute as well, but I will be adding a new tip as often as possible. I’ve got maybe 20 tips in store right now, and I’m writing new ones all the time. So without further ado, here’s…
Tip 1: Save GATC In A Constant String Macro This is an easy one, and everyone should already be doing this in one way or another.
(Update 19 November 2018: See this article for a more elegant solution.)
If you know your JavaScript, you know that all variables, functions, objects, resources, and data in the document get rewritten with every page load. In other words, every single page refresh builds the page from scratch, and the state of the document before the page refresh is left drifting in the ocean of oblivion.
Google Tag Manager’s dataLayer is also one such entity.
There’s a much easier, native-to-GTM way to do this now: the Matches CSS Selector.
Behind this tragically boring title is a simple solution to many problems with Google Tag Manager’s auto-event tracking. The common denominator to these problems is poor website markup. Selectors are used sparingly, and element hierarchy is messy. This disregard for proper node relationships means you have to resort to Data Layer Variable Macros which look like
(UPDATE 1 Oct 2014 Due to a change in how macros work in Debug Mode, the {{generic event handler}} macro no longer works when testing in Debug Mode. That means that you’ll have to test your custom listener in a live container (I know, ouch!). If you want to test in Debug Mode, you’ll have to skip using the {{generic event handler}} as a macro, and instead copy the inner function into the Custom HTML Tag, give the function a name, and use that as the callback in addEventListener or attachEvent.