gtag Custom Event Not Firing Before External Page Redirect

When you’re running a website and tracking interactions, gtag (Google Analytics tracking code) plays a key role in understanding user actions. From button clicks to submission forms, capturing these interactions provides valuable insights on improving your site.

Yet, one common issue arises when trying to track button clicks that redirect users to external pages — the gtag custom event may not fire properly before the actual redirection happens. Let’s break down what’s happening and how you can effectively solve this.

Understanding Custom Events in gtag

In Google Analytics, custom events are user interactions that your default tracking might not capture automatically. They can include things like playing a video, clicking a particular link, or downloading a file.

Tracking custom events is crucial because it helps you understand how users interact with specific elements of your page. For instance, tracking custom events lets you know whether users interact more often with your primary Call-to-Action button or whether they’re clicking away to external websites.

Implementing gtag Custom Event for Button Click

Say you’ve got this button on your landing page. You want to track every time someone clicks that button because it’s a critical marketing funnel step. To do this, you would typically add a gtag event to your button click handler.

Here’s a basic example of gtag custom event tracking for a button click:

<button id="track-btn">Learn More</button>

<script>
document.getElementById('track-btn').addEventListener('click', function() {
    gtag('event', 'button_click', {
        'event_category': 'engagement',
        'event_label': 'Learn More Button'
    });
});
</script>

This code successfully registers the event every time the button is pressed. It should fire smoothly—provided there’s no immediate action following the click.

Handling External Page Redirects with gtag Custom Events

However, the challenge arises when clicking this button immediately redirects users to an external site. Why does this matter? Because Google Analytics event tracking requests may not complete before the browser redirects the user, causing your event data to never reach your analytics dashboard.

Let’s say your button directs users to an external partner site:

<button id="external-link">Visit Partner Site</button>

<script>
document.getElementById('external-link').addEventListener('click', function() {
    gtag('event', 'external_click', {
        'event_category': 'outbound',
        'event_label': 'Partner Site'
    });
    window.location.href = "https://external-site.com";
});
</script>

Here, the event might trigger—but the user is instantly redirected, not providing enough time for the event tracking request to complete. The browser moves too quickly, abandoning the event call halfway through.

Troubleshooting Why gtag Custom Events Aren’t Firing

If you’re seeing blank or inaccurate readings in Google Analytics after implementing your events, consider the following common reasons:

• Incorrect or incomplete event code parameters.
• The gtag library script isn’t properly loaded or placed at the wrong place on the webpage.
• The page redirect occurs faster than the tracking request can go through.

To figure this out, inspect your page load thoroughly. Use your browser’s developer tools, particularly the Network tab, to see if calls to Google’s /collect endpoint are successful or if they’re failing prematurely.

Also, make sure all required parameters like “event_category” and “event_label” are correct and included, as missing parameters can sometimes prevent events from firing as expected (details from Stack Overflow).

Solving the Issue: Firing gtag Events Before External Redirect

Fortunately, Google Analytics provided a built-in solution—the event_callback parameter. This allows you to delay your redirect slightly to ensure the event has sufficient time to fire:

<button id="external-link">Visit Partner Site</button>

<script>
document.getElementById('external-link').addEventListener('click', function(e) {
    e.preventDefault(); // Stop the immediate redirect
    var externalUrl = "https://external-site.com";

    gtag('event', 'external_click', {
        event_category: 'outbound',
        event_label: 'Partner Site',
        transport_type: 'xhr',
        event_callback: function() {
            document.location = externalUrl;
        }
    });

    // Backup timeout in case the Analytics call lags
    setTimeout(function(){
        document.location = externalUrl;
    }, 1000);
});
</script>

Here’s what’s happening above:

• First, preventDefault() stops immediate browser redirection.
• event_callback() waits until Google Analytics successfully receives the event tracking request, then redirects.
• The “transport_type” parameter set to “xhr” ensures the event request completes successfully even during redirect scenario.
• A backup setTimeout() guards against longer wait times, ensuring the user isn’t left hanging in case something happens with the tracking call.

Testing and Verifying Your gtag Implementation

Don’t forget to thoroughly test after making adjustments. Check whether tracking events are indeed sending correctly:

1. Open browser developer tools (right-click → Inspect → Network tab).
2. Click your button and watch for requests to Google’s analytics servers (look for “collect?v=…”).
3. Confirm the event fires before navigating away. The status code should be “200” (successful).

Also, you can use the Google Analytics Real-Time dashboard to verify event tracking after each test interaction.

Accurate Event Tracking Means Smarter Decisions

Properly tracking custom events significantly enhances your website analytics accuracy. By understanding which buttons resonate with users or drive external clicks, you can better strategize your website content and structure.

Additionally, make sure to frequently audit your implementation. Browser updates, script placements, or analytics updates can occasionally disrupt previously successful tracking methods (explore more about JavaScript tracking here).

Now, ensuring your gtag events fire correctly—even before external redirects—is manageable by tweaking your implementation as shown. Take the time now to check your analytics setup and avoid losing any valuable insights.

Let me know—have you solved similar issues? How do you typically ensure your analytics events get captured reliably?