Demo of Sup.js

Save URL Parameters (Sup.js) is a tool that detects URL parameter values at the start of a web session, then inserts them into any form at any point in the session.

If the hidden fields are empty, reload with some URL parameters, navigate around the site for a bit, then return to see the magic.

Sample Form

[Visible fields go here...]

Hidden field name="utm_source"
Hidden field name="utm_medium"
Hidden field name="utm_campaign"
Hidden field name="referral-code"
Hidden field name="randomParameter"

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[Submit Button Goes Here]

Notes

• On actual forms these fields should hidden with attribute type="hidden".
• This works even if you visit different pages and then return.
• Sup.js works with any URL parameter—not just UTM codes—as long as there is a field with a matching name attribute.
• URL parameter values are stored for the duration of a visit (session).
• A 3-second delay gives the form more time to load. Useful for third-party forms.
• Read the accomanying article for usage examples and installation instructions.