Tracking Outbound Links in GTM

Tracking outbound link clicks in Google Tag Manager is streamlined using the Auto-Event Variable configuration.

Auto-Event Variable

Auto-Event variables access the target element of an automatic event (e.g., Click, Error, Form Submit). When configuring, you must specify the required element component:

• Element: Accesses the DOM element itself (stored as gtm.element in the Data Layer). You can create custom variables to traverse the DOM, such as gtm.element.parentElement.id to fetch a parent’s ID. Note: Built-in variables like Click Element and Form Element serve the same purpose.
• Element Classes: Returns the class attribute (gtm.elementClasses). Equivalent to the Click Classes built-in variable.
• Element ID: Returns the id attribute (gtm.elementId). Equivalent to the Click ID built-in variable.
• Element Target: Returns the target attribute (gtm.elementTarget).
• Element Text: Returns the textContent or innerText of the element. The value is trimmed and normalized for cross-browser consistency.
• Element URL: Returns the href or action attribute (gtm.elementUrl). You can further parse this to access specific URL components.
• History New/Old URL Fragment: Captures the URL fragment (hash) before or after a browser history change (gtm.newUrlFragment / gtm.oldUrlFragment).
• History New/Old State: Returns the state object from history events (gtm.newHistoryState / gtm.oldHistoryState).
• History Change Source: Identifies the event that triggered the history change (popstate, pushState, replaceState, or polling).

Returns

The variable returns the value of the selected component. If no auto-event is active, it returns the specified default value or undefined.

Tracking Outbound Links via Auto-Event Variable

This method utilizes the Element URL variable type. While it typically returns the href, the Is Outbound component type automates external link detection.

The variable returns true if the clicked link’s domain differs from the current domain, and false otherwise. This allows for precise triggering in Just Links triggers.

Implementation Steps

Step 1: Create the Auto-Event Variable

1. Navigate to Variables > User-Defined Variables > New.
2. Select Auto-Event Variable as the template.
3. Select Element URL as the Variable Type.
4. Set Component Type to Is Outbound.
5. Affiliated Domains: Enter a comma-separated list of domains (e.g., your blog or subdomain) that should be treated as internal.
6. Name the variable (e.g., Outbound Link Check) and save.

Step 2: Create the Just Links Trigger

1. Navigate to Triggers > New and select Click – Just Links.
2. Enable Wait for Tags and Check Validation for better reliability.
3. Set the trigger to fire on Some Link Clicks.
4. Define the condition: Outbound Link Check equals true.

Once configured, any tag associated with this trigger will execute only when a user clicks a link leading to an external domain.

Technical Requirement

The href attribute must contain a valid URL. Non-standard links, such as mailto: or javascript:void(0), are not classified as outbound links by this variable.