{"id":153225,"date":"2025-03-24T07:33:18","date_gmt":"2025-03-24T07:33:18","guid":{"rendered":"https:\/\/peraltafinancing.com\/analytics\/variable-guide-for-google-tag-manager\/"},"modified":"2025-03-24T07:33:18","modified_gmt":"2025-03-24T07:33:18","slug":"variable-guide-for-google-tag-manager","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=153225","title":{"rendered":"Variable Guide For Google Tag Manager"},"content":{"rendered":"


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(Updated 21 February 2019)<\/em><\/p>\n

The current version<\/a> of Google Tag Manager<\/a> was released in October 2014. With the release, we saw a brand-spanking new UI, a lot of new functionalities (revamped auto-event tracking<\/a>, for example), plus a new terminology to cope with. We moved away from the programming-centric concepts of Macros<\/em> and Rules<\/em> to the more tactile variables<\/em> and triggers<\/em>.<\/p>\n

It\u2019s difficult to rank the changes. The new Auto-Event Tracking<\/a> is perhaps most impactful, but the improvements done to triggers and variables, when compared to the previous version of GTM, require attention as well.<\/p>\n

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<\/p>\n

\"variable<\/p>\n

<\/a><\/p>\n<\/div>\n

Thus, I give you my variable Guide for Google Tag Manager. For reference, feel free to take a look at the old macro guide<\/a>, since especially the different variable types have been left largely untouched.<\/p>\n


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Introduction to Variables<\/h2>\n

In computing terms, variables<\/em> denote compartments in computer memory, which are reserved for storing values. This is a significant achievement in efficiency, because it means that values can be reused across functions, procedures, and environments. The alternative would be to treat each representation of the same value as unique, temporary, and disposable, creating a mass of redundancy and inefficiency, and making the current computing landscape a whole lot different.<\/p>\n

In Google Tag Manager, the term variable<\/em> is used to denote a helper function that your tags, triggers, and other variables can invoke to retrieve values from. Thus, the idea is very similar to the broader concept of computing variables<\/em> explored in the previous paragraph.<\/p>\n

In GTM, invoking the variable function is done with a specific syntax:<\/p>\n

{{variable name}}<\/strong><\/p>\n

As we\u2019ll learn later on, you can\u2019t invoke variables wherever you\u2019d want to. But in an approved context, the syntax {{variable name}}<\/strong> would run the underlying function of the variable with the name \u201cvariable name\u201d, and pass the value returned by that function to its execution context (the tag, trigger, or variable where the syntax was used).<\/p>\n

One of the first things all Google Tag Manager containers which run Google Analytics<\/a> tags should do is this:<\/p>\n

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<\/p>\n

\"constant<\/p>\n

<\/a><\/p>\n<\/div>\n

Here, instead of always typing the tracking code for your web property (UA-XXXXXX-X) into each GA tag, you can create a Constant variable, which stores the value. Thus, whenever the variable name is invoked using the correct syntax, the tracking code returned by the Constant variable will be included in the appropriate tag field. This is something I\u2019ve actually written a #GTMtips post<\/a> about this.<\/p>\n

I will go so far as to say that variables can make or break GTM. When skeptics ask me what is the main benefit of having GTM on the site, I always end up talking about variables. They add a level of flexibility and customization that can really make your tagging lean, efficient, performance-driven, and time-saving.<\/p>\n

At the same time, variables can be difficult to fathom, especially when we get to the technical details (see below), or when we try to tackle the amazingly multi-faceted and deviously difficult Custom JavaScript variable. I hope this guide will help you get to the bottom of variables, and encourage you to find your own ways of performing magic<\/a> tricks with your GTM container.<\/p>\n

Technical details and how-to<\/h2>\n

For you to be able to invoke a GTM variable, you need to be working in a script context<\/em>, or the template field needs to support variable references.<\/p>\n

A supported template field can be uncovered by looking for the little variable symbol next to a field:<\/p>\n

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<\/p>\n

\"variable<\/p>\n

<\/a><\/p>\n<\/div>\n

As you can see, the \u201cTag firing priority\u201d field will not<\/em> be able to invoke a variable, but the \u201cAuto Link Domains\u201d will. In fact, if you click the little variable icon, you will see a drop-down list from which you can pick the variable you want to use. This way you don\u2019t have to worry about correct syntax, as GTM will do it for you.<\/p>\n

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<\/p>\n

\"variable<\/p>\n

<\/a><\/p>\n<\/div>\n

The other places where you\u2019ll frequently run into variables are:<\/p>\n

    \n
  1. \n

    Triggers<\/p>\n<\/li>\n

  2. \n

    Custom HTML tags<\/p>\n<\/li>\n

  3. \n

    Custom JavaScript variables<\/p>\n<\/li>\n<\/ol>\n

    With triggers (remember to read my Trigger guide<\/a> as well!), you will always need to specify a variable as the target of the trigger condition. Every single trigger condition needs a variable that is evaluated against some value. In fact, the condition builder is created so that you can\u2019t possibly not<\/em> choose a variable. It\u2019s obligatory!<\/p>\n

    \n

    <\/p>\n

    \"trigger<\/p>\n

    <\/a><\/p>\n<\/div>\n

    Note that the value<\/strong> (right-hand) field of the trigger condition is NOT<\/strong> a variable context!<\/p>\n

    As for Custom HTML tags and Custom JavaScript variables, you can call variables from the scripts within, but you won\u2019t have the helpful drop-down menu to assist you. You will need to manually type the call, using the correct syntax and the correct (case-sensitive) variable name:<\/p>\n

    \n
    <\/span>\nscript>\n  (function<\/span>() {\n    alert({{custom alert string}});\n  })();\nscript<\/span>><\/code><\/pre>\n<\/div>\n
    The code above will pop-up a browser alert, where the content will be the string returned by the variable named custom alert string<\/strong>. Note! If the variable doesn\u2019t return a string, you might run into problems with the alert<\/code> method, so you need to be well aware of return types and values at all times.<\/p>\n
    If you try to use a variable that doesn\u2019t exist (or whose name you mistyped), you won\u2019t be able to perform any operations on the container version (create, publish, etc.). You\u2019ll run into an error message that looks like this:<\/p>\n
    \n
        <\/p>\n
        \"variable<\/p>\n
        <\/a><\/p>\n<\/div>\n
    So remember to check all the places where you\u2019ve manually typed a variable call. It\u2019s also possible that you\u2019ve jumped the gun and called a variable, but then you forgot to create the variable itself. Retrace your steps and fix any broken links.<\/p>\n
    One cool thing that GTM does for you is this: when you change a variable name, all<\/strong> references to the variable are automatically updated. Even the ones you\u2019ve typed in manually into Custom HTML tags and Custom JavaScript variables! This is incredibly time-saving, since you don\u2019t have to go through every single reference, rewriting the code to match the new name.<\/p>\n
    Variables are resolved<\/strong> according to the following process:<\/p>\n