Updated 25 May 2021: Added information about using this with GA4. As Google Analytics 4 does not have a mechanism to disable cookie storage, only the second solution (send dataLayer events from iframe to the parent) described in this article will work for GA4.
Here I am, back with <iframe> and cross-domain tracking. I’ve published a couple of articles before on the topic, with my upgraded solution being the most recent one.
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Update 6 April 2020: I updated the template in the gallery to the latest version of the IP Geolocation API SDK, which no longer requires jQuery. Also, the SDK now handles API request caching to browser storage automatically, so the “Enable Session Storage” option was added to the template.
Google Analytics had been foreshadowing the deprecation of the Network Domain and Service Provider custom dimensions since late 2019. On February 4, the plug was finally pulled, and both these dimensions started flatlining to (not set) in Google Analytics reports.
One of the most prominent features of Google Tag Manager since the dawn of time (actually, late 2012) is the Custom HTML tag. This little piece of magic lets Google Tag Manager inject an HTML element to the page. Since time immemorial (still late 2012), it’s allowed us to turn Google Tag Manager from a sandboxed prisoner of the native tag templates to a no-holds-barred client-side content management solution.
In this article, we’ll discuss how the Custom HTML tag works, and what you might be tempted to use it for.
One of the prime things to use Google Tag Manager for is script injection. Loading a third-party JavaScript library is trivial to do with a Custom HTML tag, and works like a charm.
However, using Custom HTML tags for, well, anything, is no longer the preferred way to add custom code to the site. Custom HTML tags are pretty expensive DOM injections, and they can be incredibly dangerous tools (for UX, security, and privacy) in the wrong and/or inexperienced hands.
Update 6 April 2020: I updated the template in the gallery to the latest version of the IP Geolocation API SDK, which no longer requires jQuery. Also, the SDK now handles API request caching to browser storage automatically, so the “Enable Session Storage” option was added to the template.
My latest custom tag template tackles a use case I’ve referred to a number of times before, especially in my article on sending weather data to Google Analytics.
Update 17 February 2020: Google Tag Manager’s Preview mode cookies have been updated with the necessary flags, so they will not break once SameSite enforcement begins.
If you’ve opened the browser console in Google Chrome (since Chrome 76), you might have seen a bunch of warnings in a yellow background related to something called a SameSite cookie attribute that is either missing or incompletely set for cookies set on external domains.
Universal Analytics utilizes two components (by default) to attribute a browser session to a specific campaign: query parameters in the URL and the referrer string.
The page URL is sent with every hit to Google Analytics using the Document location field, which also translates to the &dl parameter in the Measurement Protocol.
The referrer string is sent with a hit to Google Analytics using the Document referrer field, as long as the referrer hostname does not exactly match that of the current page and the referrer string is not empty.