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What does it do?

It adds UTM, referrer, landing page and other information to any lead generation form. It adds this extra information as hidden fields on a form.

Here's a blog post discussing it in detail:

Why do I need it?

If you want to know where each email list subscriber or lead is coming from, use this script to help with that. This is different from analytics tools where you know this information in aggregate.

e.g. You'll know that originally came from Twitter, landed on page and visited your website 3 times before giving you his email address.

Information it adds to your forms:

  • 5 UTM parameters - Any UTM parameters in the URL that a visitor used to come to your website will be added to the form
  • 5 Initial UTM parameters (optional) - The UTM parameters in the very first URL that the visitor used
  • Initial Referrer - The webpage where the visitor came from for the first time
  • Last Referrer - The webpage where the visitor came from most recently
  • Initial Landing page - URL of the page on your website where the visitor landed the very first time
  • Number of visits - The number of times the visitor came to your website before filling your form
  • Additional parameters defined in additional_params_map
  • Additional initial parameters defined in additional_initial_params_map

How do I use it?

  1. Just add this before the closing </body> tag at the bottom of your page. Make sure to change the domain.
<script type="text/javascript" charset="utf-8">
  var _uf = _uf || {};
  _uf.domain = "";

<script src="" async></script>

There might be newer versions available in dest folder that are not yet available via CDN. Feel free to download the latest files in that case.

  1. You need to make your forms accept the new fields. Based on the information available for a visitor, the fields added to your form will be,
  • USOURCE - Value of utm_source if present
  • UMEDIUM - Value of utm_medium if present
  • UCAMPAIGN - Value of utm_campaign if present
  • UCONTENT - Value of utm_content if present
  • UTERM - Value of utm_term if present
  • IREFERRER - URL of the initial referrer
  • LREFERRER - URL of the last referrer
  • ILANDPAGE - Initial landing page
  • VISITS - Number of visits

Note: A new visit happens when the visitor comes to your website after more than an hour (can be customized as shown below).

How will my form look like?

Let's say your lead generation form looks like this before the script is added.

<form action="//" method="post">
  <label for="mce-email">Email Address</label>
  <input type="email" value="" name="email" id="mce-email">
  <input type="submit" value="Subscribe" name="subscribe">

Once the script is added, your form will look like this after the page is loaded.

<form action="//" method="post">
  <input type="hidden" name="VISITS" value="5">
  <input type="hidden" name="IREFERRER" value="http%3A//">
  <input type="hidden" name="LREFERRER" value="http%3A//">
  <input type="hidden" name="ILANDPAGE" value="http%3A//">
  <input type="hidden" name="USOURCE" value="twitter">
  <input type="hidden" name="UMEDIUM" value="social">
  <input type="hidden" name="UCAMPAIGN" value="awareness">

  <label for="mce-email">Email Address</label>
  <input type="email" value="" name="email" id="mce-email">
  <input type="submit" value="Subscribe" name="subscribe">

When someone submits the form, all the extra information is also sent along with the email address.

You'll need to make sure that your form can accept these values. If it is a Mailchimp form, configure it to accept these fields. Same for ConstantContact, CampaignMonitor, Hubspot, ActiveCampaign or any other service.

Customize your forms

If you would like to customize how fields get added to your form, following options are available:

<script type="text/javascript" charset="utf-8">
  var _uf = _uf || {};
  _uf.domain                     = "";

  _uf.utm_source_field           = "YOUR_SOURCE_FIELD"; // Default 'USOURCE'
  _uf.utm_medium_field           = "YOUR_MEDIUM_FIELD"; // Default 'UMEDIUM'
  _uf.utm_campaign_field         = "YOUR_CAMPAIGN_FIELD"; // Default 'UCAMPAIGN'
  _uf.utm_content_field          = "YOUR_CONTENT_FIELD"; // Default 'UCONTENT'
  _uf.utm_term_field             = "YOUR_TERM_FIELD"; // Default 'UTERM'

  _uf.initial_utm_params         = true; // Enable the tracking of initial UTM Parameters
  _uf.initial_utm_source_field   = "YOUR_INITIAL_SOURCE_FIELD"; // Default 'IUSOURCE'
  _uf.initial_utm_medium_field   = "YOUR_INITIAL_MEDIUM_FIELD"; // Default 'IUMEDIUM'
  _uf.initial_utm_campaign_field = "YOUR_INITIAL_CAMPAIGN_FIELD"; // Default 'IUCAMPAIGN'
  _uf.initial_utm_content_field  = "YOUR_INITIAL_CONTENT_FIELD"; // Default 'IUCONTENT'
  _uf.initial_utm_term_field     = "YOUR_INITIAL_TERM_FIELD"; // Default 'IUTERM'

  _uf.initial_referrer_field     = "YOUR_INITIAL_REFERRER_FIELD"; // Default 'IREFERRER'
  _uf.last_referrer_field        = "YOUR_LAST_REFERRER_FIELD"; // Default 'LREFERRER'
  _uf.initial_landing_page_field = "YOUR_INITIAL_LANDING_PAGE_FIELD"; // Default 'ILANDPAGE'
  _uf.visits_field               = "YOUR_VISITS_FIELD"; // Default 'VISITS'
  _uf.additional_params_map      = {
    affiliate: "AFFILIATE"
  }; // Maps affiliate parameter to AFFILIATE form field
  _uf.additional_initial_params_map      = {
    affiliate: "IAFFILIATE"
  }; // Maps the initial affiliate parameter to IAFFILIATE form field                     = true; // Enable secure cookies
  _uf.sessionLength              = 2; // In hours. Default is 1 hour
  _uf.add_to_form                = "first"; // 'none', 'all', 'first'. Default is 'all'
  _uf.form_query_selector        = 'form[action="/sign_up"]'; // custom form selector. Default is 'form', to select any form.
  _uf.decode_uris                = true; // Decode URLs before populating the form. e.g. use "https://" instead of "https%3A//".
                                         // NOTE: This will decode the entire URL and, in rare cases, may have side effects.

<script src="" async></script>

More Questions?

What happens if someone visits a bunch of pages on my website/blog before filling the form?

It doesn't matter. As soon as they land on your website, the script saves the information in a cookie. This cookie is valid for 365 days. It adds this information to your form from the saved cookie.

What's the session length for?

It's used to count the number of visits. If someone comes to your website after the session has expired, it will be counted as a new visit.

Can I look at the code?

You are on Github and all the code is available above. Knock yourself out. Even better, send a pull request and we can make it better together.


Utm Form is written in CoffeeScript and compiles to Javascript.


  1. Clone the repository
  2. Make sure you have node and npm installed: brew install node.
  3. Install the required packages: npm install.


Run gulp build

This will compile the CoffeeScript and also minify it. The generated files can be found in dest folder.


Add UTM, referrer, landing page and other information to any lead generation form




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