How can I track a form's source in Webflow using hidden fields?

To track the source of a form submission in Webflow, you can use hidden form fields combined with custom JavaScript or UTM parameters. Here’s how to set it up:

1. Add Hidden Fields to Your Webflow Form

• Open your form in the Webflow Designer.
• Drag a Form Block (or open an existing form).
• Add hidden form fields using the "Add Field" panel.
• Set the Field Type to Hidden.
• Give each field a clear Name and ID such as:
• utm_source
• utm_medium
• utm_campaign
• referrer

2. Capture UTM Parameters via JavaScript

To auto-fill the hidden fields with UTM values:

• Add the following JavaScript to your Page Settings → Custom Code → Footer section:
• This script reads UTM parameters from the URL and assigns them to the hidden fields.
• Sample code concept:
• Parse window.location.search
• For each UTM (like utm_source), match it to a corresponding hidden field by ID.
• Use document.getElementById('utm_source').value = ... to assign values.

3. Capture Referrer URL (Optional)

To log the referring page (if no UTM tags are present):

• In the same script, use:
• document.getElementById('referrer').value = document.referrer
• This captures the URL of the page that led the visitor to your form page.

4. Save and Publish Your Site

• Save all form and script changes.
• Publish your Webflow site to test the actual implementation.
• Open a URL with UTM parameters (e.g., ?utm_source=facebook) and check that the values auto-fill the hidden inputs.

5. Validate via Form Submissions

• Submit a test form.
• Check your form submission entries in Webflow’s Forms tab or your connected tools (e.g., Zapier, Make, integrations).
• You should see the hidden field values alongside the submission.

Summary

To track a form's source in Webflow, add hidden form fields and use JavaScript to auto-populate them with UTM parameters or the document.referrer. This lets you track which marketing channels or links contributed to form submissions without altering user-facing fields.