Tutorials

How to implement the GrowSurf JavaScript SDK in common use-case scenarios.

Table of contents

Scenario
Example 1: Trigger a referral on qualifying action (e.g, on conversion, purchase or upgrade)
Example 2: Open the GrowSurf window on button click
Example 3: Display a participant's unique share link and referral count inline on a webpage
Example 4: Redirect to another URL after a successful participant signup
Example 5: Add a personalized message to your Share URL for a warm welcome
Example 6: Only add a participant if they were referred
Example 7: Hide the GrowSurf Embedded Form until a GrowSurf participant is detected
Example 8: Add internationalization support for the GrowSurf Embedded Form and Embedded Invite
Example 9: Update pre-populated share and email invite messages to capitalize on a customer "aha moment"
Example 10: Load multiple GrowSurf campaigns on a single webpage
Example 11: Display a referral link on your login page

Example 1: Trigger a referral on qualifying action (e.g, on conversion, purchase, or upgrade)

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add the participant

Important Note: If your campaign is configured to add participants automatically through a form on your website (see image), skip this step.

First, in the code where you capture the referred friend's email address, add them to your GrowSurf campaign as a participant with growsurf.addParticipant(). Let's say you have a signup function called signUpFree(), here's what that looks like:

your-script.js

// In this example, a new person is just signing up for a free account
const signUpFree = (user) => {
    // ...code that registers a new user...
    // Then add the new user as a participant in your GrowSurf campaign
    if (window.growsurf) {
        growsurf.addParticipant({
            email: user.email,
            firstName: user.firstName,
            lastName: user.lastName
        });
    }
};

Behind the scenes, the GrowSurf Universal Code will associate the referrer (if they exist) with the new participant. At any future date within the referral credit window, if this new participant triggers a referral, GrowSurf will provide credit to the referrer.

Step 3: Trigger the referral

Then, in the code where the action takes place, trigger the referral with growsurf.triggerReferral() . Let's say you have a function called upgradeToPaidPlan(), here's what that looks like:

your-script.js

// In this example, the user upgrades to a paid plan
const upgradeToPaidPlan = (user) => {
    // ...code that upgrades the user...
    // Then trigger this action as a referral trigger
    if (window.growsurf) {
        growsurf.triggerReferral(user.email);
    }
};

Important Note: Make sure your campaign's referral trigger is set to Sign Up + Qualifying Action (see image). If the referral trigger is set to Sign Up, triggering referrals will not work since referral credit has already been provided.

Remember to set up reward fulfillment automation

Make sure you have Webhooks or Zapier set up so that rewards automatically get fulfilled to the participant once they reach a reward goal.

Example 2: Open GrowSurf window on button click

Sometimes you want people to access your referral campaign from any webpage. Or perhaps you just want to use buttons that look native to your website's branding instead of using the GrowSurf floating widget button.

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

Use Embeddable Elements

Add the Embedded Button anywhere in your HTML

Just paste <div data-grsf-block-button></div> anywhere in your HTML, and clicking the element will open up the GrowSurf window.

index.html

<!-- Here's the simplest solution -->
<div data-grsf-block-button></div>

<!-- Here's a customized solution -->
<div data-grsf-block-button
 data-grsf-button-style="{'background-color': '#117a8b', 'font-family': 'Arial', 'color': '#FFFFFF', 'border-radius': '6px' }"
 data-grsf-button-text="Join My Referral Program">
</div>

Use JavaScript

Add onclick="growsurf.open()" to any HTML element

Just add onclick="growsurf.open()" to any HTML element, and clicking it will open up the GrowSurf window.

index.html

<!-- Works on any HTML element. Here's a <div> example: -->
<div onclick="growsurf.open()">Refer Friends</div>

<!-- Here's a <button> example: -->
<button onclick="growsurf.open()">Refer Friends</button>

Example 3: Display a participant's unique share link and referral count inline on a webpage

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

Use Embeddable Elements

Add the Embedded Form anywhere in your HTML

Just paste <div data-grsf-block-form></div> anywhere in your HTML, and the GrowSurf form will appear. If you want your participant to be already logged in and see their stats (instead of the form), you can add an attribute data-grsf-email to have the value of the participant's email.

Important Note:

If you have participant authentication enabled for your campaign, then the participant's unique share link and social buttons will only display if the participant entered your referral program from their browser (either through automatic form detection, the GrowSurf form, or the JavaScript SDK). This is because a browser cookie will be saved that identifies the participant. Otherwise, the signup form will be shown, and the participant can click the login link to get sent a one-time login email.

index.html

<!-- Providing just this code will make the GrowSurf form appear -->
<div data-grsf-block-form></div>

<!-- Add a `data-grsf-email` attribute to authenticate the participant -->
<div data-grsf-block-form
 data-grsf-email="[e-mail]">
</div>

<!-- You can also completely customize the Embedded Form, shown in this example -->
<div data-grsf-block-form
 data-grsf-email="[e-mail]"
 data-grsf-button-style="{'background-color': '#5890E7', 'color': '#fcfcfc', 'font-family': 'Sans', 'font-size': '12px'}"
 data-grsf-email-button-style="{'background-color': '#5890E7', 'color': '#fcfcfc', 'font-family': 'Arial', 'font-size': '12px'}"
 data-grsf-email-button-text="Share"
 data-grsf-twitter-button-style="{'background-color': '#5890E7', 'font-family': 'Arial', 'font-size': '12px'}"
 data-grsf-twitter-button-text="Share"
 data-grsf-facebook-button-style="{'background-color': '#5890E7', 'font-family': 'Courier New', 'font-size': '12px'}"
 data-grsf-facebook-button-text="Share"
 data-grsf-pinterest-button-style="{'background-color': '#5890E7', 'letter-spacing': '1.2', 'font-size': '12px'}"
 data-grsf-pinterest-button-text="Pin It"
 data-grsf-share-instructions="Share this unique link with your friends">
</div>

Use JavaScript

Call growsurf.getParticipantByEmail()

Fetch a participant's information using growsurf.getParticipantByEmail().

Here's an example of retrieving the participant data, then updating the #share-url and #referral-count HTML elements to show their unique referral link and referral count.

index.html

<!DOCTYPE html>
<html>
<head>
	<title>Your Referral Stats</title>
	<!-- The GrowSurf Universal Code -->
	<script type="text/javascript">
		(function(g,r,s,f){g.growsurf={};g.grsfSettings={campaignId:"REPLACE_ME_WITH_YOUR_CAMPAIGN_ID",version:"2.0.0"};s=r.getElementsByTagName("head")[0];f=r.createElement("script");f.async=1;f.src="https://growsurf.com/growsurf.js"+"?v="+g.grsfSettings.version;f.setAttribute("grsf-campaign", g.grsfSettings.campaignId);!g.grsfInit?s.appendChild(f):"";})(window,document);
	</script>
</head>
<body>
	<input id="share-url" type="text" disabled>
	<div id="referral-count"></div>
	
	<script>
	    // Listen and wait for Growsurf to initialize
	    window.addEventListener('grsfReady', () => {
	        const participantEmail = '[e-mail]'; // replace with your user's email
        	// Get the GrowSurf participant's information
		growsurf.getParticipantByEmail(participantEmail).then(participant => {
			document.getElementById("share-url").value = participant.shareUrl;
			document.getElementById("referral-count").innerHTML = participant.referralCount;			
		});
	    });	
	</script>
</body>
</html>

Example 4: Redirect to another URL after a successful participant signup

This is for when you want to redirect to another webpage after a participant successfully signs up for your referral campaign.

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

Use Embeddable Elements

If you are using the Embedded Form, you can add the following HTML attribute: data-grsf-redirect-url.

Remember to replace https://replaceme.com with your redirect URL.

<div data-grsf-block-form
 data-grsf-redirect-url="https://replaceme.com">
</div>

Use JavaScript

If you are using your own form via automatic form detection or JavaScript Web API, then include the following snippet of code within the <HEAD> of the HTML source code. This should be the same page(s) where you have included the GrowSurf Universal Code. Remember to replace https://replaceme.com at line 7 with your redirect URL.

<script>
    // Listen and wait for the Growsurf Universal Code to initialize
    window.addEventListener('grsfReady', () => {
        console.log('GrowSurf is Ready!');
        // Your redirect code goes here....
        growsurf.subscribe('signup', (participant) => {
          window.location.replace("http://replaceme.com");
        });
    });
</script>

Please note that if the redirect is not working, it is most likely because the form submission is failing. If this is the case, please check your browser console for errors.

Example 5: Add a personalized message to your Share URL for a warm welcome

When a new visitor lands on your site using their friend's unique link, you can personalize a message for them with growsurf.getReferrerId() and growsurf.getParticipantById(). In this example, we have a simple page with a h1#header that will display as "Emily S. invited you to pet puppies on-demand" if a referrer exists, otherwise it will display as "Pet puppies on-demand".

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

index.html

<html>
	<body>
		<h1 id="header">Pet puppies on-demand</h1>
	</body>
	<script>
		window.addEventListener('grsfReady', () => {
			const referrerId = growsurf.getReferrerId();	
			if (referrerId) {
				growsurf.getParticipantById(referrerId).then(participant => {
					if (participant) {
						const { firstName, lastName = '' } = participant;
						const lastNameAsString = (lastName).toString();
						const newHeader = `${firstName && lastName ? firstName + ' ' + lastNameAsString.charAt(0) + '. invited you to pet puppies on-demand' : 'Pet puppies on-demand'}`;
						const headerEl = document.getElementById('header');
						headerEl.innerHTML = newHeader;
					}
				});
			}
		});
	</script>
</html>

Example 6: Only add a participant if they were referred

In this example, we will only add a participant if they were referred by another participant within your campaign. We will utilize the GrowSurf functions growsurf.getReferrerId() and growsurf.addParticipant() to do this.

Here we are only adding the participant but if you wish to trigger a referral replace the growsurf.addParticipant()method with growsurf.triggerReferral() in the example below. The example code also assumes that you have set up a submit listener on your form which will listen for submission events and invoke the callback function described below. If you are not sure how to add a form submission listener here is an example.

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

This code is for demonstration purposes only. You may need to modify it to work on your website.

index.html

<html>
	<body>
		<h1 id="header">Pet puppies on-demand</h1>
		<!-- Example form only, this must be replaced with your actual form -->
		<form id="form">
	  		<label>Email: <input name="email" type="text"></label>
  			<button type="submit">Submit form</button>
		</form>
	</body>
	<script>
		// Listen for the GrowSurf Ready Event
		window.addEventListener('grsfReady', () => {
			// Add an event listener to the example form to listen for submissions
			const form = document.getElementById('form');
			form.addEventListener('submit', onFormSubmit);
		});
		
		// Callback function that is invoked when a new visitor has just submitted a form on your website
		const onFormSubmit = (event) => {
		    // Get the value of the email - Update this depending on your form
		    const userEmail = event.target.email.value;
		    // Check to see if the submitter was referred
		    if (window.growsurf && !!window.growsurf.getReferrerId()) {
		        // Only Add the participant if they were referrered
		        window.growsurf.addParticipant({ email: userEmail });
		    }
		    event.preventDefault();
		};
	</script>
</html>

A few things to notice here are the window.addEventListener and the form.addEventListener snippets of code. The window.addEventListener listens for the GrowSurf script grsfReady event which is emitted when the GrowSurf script is ready. Once the GrowSurf script is ready we are adding a submit event listener to our form form.addEventListener to listen for submission events. You will need to get the form element using document.getElementById using the id of your form for this to work - this is just an example. The next piece of code we will look at is the onFormSubmit function that is called when our form is submitted. The getReferrerId() function provided by the GrowSurf JavaScript API is used to determine if the submitter of the form was referred. If this function returns a value we then continue to add the participant using the addParticipant() function. You will need to get the value of theuserEmail input using the id or name of the input element of your form - this is just an example. Please note that this example will attempt to add a participant on all form submissions regardless if the form is valid or not. If you wish to perform some validation before adding the participant that will require some extra coding to do so but is out of scope for this example.

Example 7: Hide the GrowSurf Embedded Form until a GrowSurf participant is detected

Let's say you are using the Embedded Form and passing an email address as a data attribute so that a participant gets created. Because GrowSurf needs to wait for a network request to finish, the signup form may be shown for a few seconds or less. To change this behavior to hide the signup form, you can use the following HTML, CSS, and JS (jQuery) code as an example below.

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

HTML

<div data-grsf-block-form
  data-grsf-email="[e-mail]"
  class="hide-until-grsf-auth"></div>

CSS

.show-after-grsf-auth { display: initial }
.hide-until-grsf-auth { display: none }

JS (jQuery)

// Check if a participant is logged-in, and display auth views based on if there is a participant
function showGrsf() {
	var participantAuth = growsurf.getParticipantId();
	if (participantAuth) {
		$('.hide-until-grsf-auth').addClass('show-after-grsf-auth');
	} else {
		// Subscribe to a 'GrowSurf signup' event listener
		growsurf.subscribe('signup', function(participant) {
		  $('.hide-until-grsf-auth').addClass('show-after-grsf-auth');
		});
	}
}

// See if GrowSurf is available
if(!window.growsurf) {
	// Listen and wait for the Growsurf Universal Code to initialize
	window.addEventListener('grsfReady', function() {
		showGrsf();
	});
} else {
	showGrsf();
}

Example 8: Add internationalization support for the GrowSurf Embedded Form and embedded invite

In this example, we'll walk through how to use GrowSurf embeddable elements to support multiple languages on your website. We will use the Embedded Form and Embedded Invite elements, customizing data attributes to display text in both English and Spanish.

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

Embedded Form

These examples only use facebook and twitter as the enabled social share buttons. If you have other social share options enabled, make sure to account for them. These examples also assume that you have a custom signup field called "Phone Number" (see image). Custom fields are supported via kebab-case (see example usage of phone-number at lines 6 and 7 in the code snippets below).

In English:

<div data-grsf-block-form
 data-grsf-field-first-name-label="First name"
 data-grsf-field-first-name-placeholder="First name"
 data-grsf-field-first-name-label="Last name"
 data-grsf-field-first-name-placeholder="Last name" 
 data-grsf-field-phone-number-label="Phone number"
 data-grsf-field-phone-number-placeholder="Phone number"
 data-grsf-share-instructions="Share this unique link with your friends"
 data-grsf-copy-link-button-text="Copy Link"
 data-grsf-email-button-text="Share"
 data-grsf-email-button-message="I just saved $X,XXX by using this service! {{shareUrl}}"
 data-grsf-email-button-subject="Check this out friend"
 data-grsf-facebook-button-text="Share"
 data-grsf-facebook-button-message="I just saved $X,XXX by using this service! {{shareUrl}}"
 data-grsf-twitter-button-text="Share"
 data-grsf-twitter-button-message="I just saved $X,XXX by using this service! {{shareUrl}}">
</div>

In Spanish:

<div data-grsf-block-form
 data-grsf-field-first-name-label="Primer nombre"
 data-grsf-field-first-name-placeholder="Primer nombre"
 data-grsf-field-first-name-label="Apellido"
 data-grsf-field-first-name-placeholder="Apellido" 
 data-grsf-field-phone-number-label="Número de teléfono"
 data-grsf-field-phone-number-placeholder="Número de teléfono"
 data-grsf-share-instructions="Comparte este enlace único con tus amigos"
 data-grsf-copy-link-button-text="Copiar link"
 data-grsf-email-button-text="Cuota"
 data-grsf-email-button-message="¡Acabo de ahorrar $X,XXX al usar este servicio! {{shareUrl}}"
 data-grsf-email-button-subject="Mira esto amigo"
 data-grsf-facebook-button-text="Cuota"
 data-grsf-facebook-button-message="¡Acabo de ahorrar $X,XXX al usar este servicio! {{shareUrl}}"
 data-grsf-twitter-button-text="Cuota"
 data-grsf-twitter-button-message="¡Acabo de ahorrar $X,XXX al usar este servicio! {{shareUrl}}">
</div>

Embedded Invite

These examples used Google as the enabled address book. If you have other address books enabled, make sure to account for them.

In English:

<div data-grsf-block-invite
 data-grsf-input-placeholder-text="Enter email addresses here"
 data-grsf-preview-link-text="Preview your message"
 data-grsf-preview-subject-label="Email Subject"
 data-grsf-preview-subject-placeholder="Check this out friend"
 data-grsf-preview-subject="Check this out friend"
 data-grsf-preview-message-label="Email Message"
 data-grsf-preview-message-placeholder="I just saved $X,XXX by using this service! {{shareUrl}}"
 data-grsf-preview-message="I just saved $X,XXX by using this service! {{shareUrl}}" 
 data-grsf-submit-button-text="Send Invites"
 data-grsf-google-button-text="Import Google Contacts"
 data-grsf-contact-picker-search-text="Search"
 data-grsf-contact-picker-suggestions-text="Suggestions"
 data-grsf-contact-picker-results-text="Results"
 data-grsf-contact-picker-load-more-button-text="Load More">
</div>

In Spanish:

<div data-grsf-block-invite
 data-grsf-input-placeholder-text="Ingrese las direcciones de correo electrónico aquí"
 data-grsf-preview-link-text="Vista previa de su mensaje"
 data-grsf-preview-subject-label="Asunto del email"
 data-grsf-preview-subject-placeholder="Mira esto amigo"
 data-grsf-preview-subject="Mira esto amigo"
 data-grsf-preview-message-label="Mensaje de correo electrónico"
 data-grsf-preview-message-placeholder="¡Acabo de ahorrar $X,XXX al usar este servicio! {{shareUrl}}"
 data-grsf-preview-message="¡Acabo de ahorrar $X,XXX al usar este servicio! {{shareUrl}}" 
 data-grsf-submit-button-text="Enviar invitaciones"
 data-grsf-google-button-text="Importar contactos de Google"
 data-grsf-contact-picker-search-text="Buscar"
 data-grsf-contact-picker-suggestions-text="Sugerencias"
 data-grsf-contact-picker-results-text="Resultados"
 data-grsf-contact-picker-load-more-button-text="Carga más">
</div>

Example 9: Update pre-populated share and email invite messages to capitalize on a customer "aha moment"

If your product has an "aha moment", this is a great time to ask for referrals. On your webpage or web app, display the Embedded Form and Embedded Invite elements to provoke the participant to share.

In this example, we will use two methods growsurf.updateSocialShareMessage() and growsurf.updateEmailInviteMessage() to update pre-populated social share messages so that the default text is more relevant to your user.

Step 1: Make sure the GrowSurf Universal Code is installed

Step 2: Add code

To better illustrate this use-case, consider the following scenarios:

Social media SaaS

Let's say you're a SaaS company that helps social media users gain more followers. You could ask for referrals once a user gains 100 followers.

Add the following HTML code (e.g, in a popup on your webpage):

<div>
    <h2>💯 Alert!</h2>
    <p>Amazing, you just hit 100 followers this past week.</p>
    <div data-grsf-block-form
         data-grsf-share-instructions="Get your next month on us when you refer a friend"
         data-grsf-copy-link-container-style="{'display': 'none'}"></div>
    <div data-grsf-block-invite></div>
</div>

Add the following JavaScript code:

// Sign up (or log in) your user as a GrowSurf participant
const userEmail = '[e-mail]'; // Replace with the user's email address
growsurf.addParticipant({email: userEmail});

// Set the initial message and subject line
const message = "I've just gained 100 followers by using this tool! {{shareUrl}}";
const subjectLine = "Check this out!";

// Update the social share messages
growsurf.updateSocialShareMessage('email', message, subjectLine);
growsurf.updateSocialShareMessage('facebook', message);
growsurf.updateSocialShareMessage('twitter', message);
growsurf.updateSocialShareMessage('pinterest', message);
growsurf.updateSocialShareMessage('sms', message);
growsurf.updateSocialShareMessage('whatsapp', message);

// Update the pre-populated email invite message and subject line
growsurf.updateEmailInviteMessage(message, subjectLine);

If you need to call this on immediate page load, wrap the JavaScript code in a grsfReady Event Listener.

Enterprise messaging app

Let's say you're a messaging SaaS (e.g, Slack). You could ask for referrals once a team sends 2,000 messages in a workspace.

Add the following HTML code (e.g, in a popup on your webpage):

<div>
    <h2>Woohoo, you've just sent 2,000 messages!</h2>
    <p>That's 6 days worth of time saved in productivity.</p>
    <div data-grsf-block-form
         data-grsf-share-instructions="Share your victory:"
         data-grsf-copy-link-container-style="{'display': 'none'}"></div>
    <div data-grsf-block-invite></div>
</div>

Add the following JavaScript code:

// Sign up (or log in) your user as a GrowSurf participant
const userEmail = '[e-mail]'; // Replace with the user's email address
growsurf.addParticipant(userEmail);

// Set the initial message and subject line
const message = "We've just sent 2,000 messages using this service and have saved 6 days of productivity. Love this service! {{shareUrl}}";
const subjectLine = "Check this out!";

// Update the social share messages
growsurf.updateSocialShareMessage('email', message, subjectLine);
growsurf.updateSocialShareMessage('facebook', message);
growsurf.updateSocialShareMessage('twitter', message);
growsurf.updateSocialShareMessage('pinterest', message);
growsurf.updateSocialShareMessage('sms', message);
growsurf.updateSocialShareMessage('whatsapp', message);

// Update the pre-populated email invite message and subject line
growsurf.updateEmailInviteMessage(message, subjectLine);

If you need to call this on immediate page load, wrap the JavaScript code in a grsfReady Event Listener.

Food delivery service

Let's say you're a food delivery service company (e.g, Doordash). You could ask for referrals once the user leaves a positive review after a delivery.

Add the following HTML code (e.g, in a popup on your webpage):

<div>
    <h2>Loving Doordash?</h2>
    <div data-grsf-block-form
         data-grsf-share-instructions="Get your next meal on us, up to $20 when you refer a friend."
         data-grsf-copy-link-container-style="{'display': 'none'}"></div>
    <div data-grsf-block-invite></div>
</div>

Add the following JavaScript code:

// Sign up (or log in) your user as a GrowSurf participant
const userEmail = '[e-mail]'; // Replace with the user's email address
growsurf.addParticipant(userEmail);

// Set the initial message and subject line
const message = "I just ordered delicious Wing's spicy noodle soup with DoorDash. 5/5 experience! Get $20 off your first order: {{shareUrl}}";
const subjectLine = "Check this out!";

// Update the social share messages
growsurf.updateSocialShareMessage('email', message, subjectLine);
growsurf.updateSocialShareMessage('facebook', message);
growsurf.updateSocialShareMessage('twitter', message);
growsurf.updateSocialShareMessage('pinterest', message);
growsurf.updateSocialShareMessage('sms', message);
growsurf.updateSocialShareMessage('whatsapp', message);

// Update the pre-populated email invite message and subject line
growsurf.updateEmailInviteMessage(message, subjectLine);

If you need to call this on immediate page load, wrap the JavaScript code in a grsfReady Event Listener.

Example 10: Load multiple GrowSurf campaigns on a single webpage

If you have multiple GrowSurf campaigns and want to use the same landing page and/or signup pages, here's how you can load the right campaign depending on where the traffic is coming from.

Step 1: Update each Share URL for each of your campaigns

For each of your campaigns, navigate to Campaign Editor > 5. Installation and update the Share URL to include a ?growsurf_campaign parameter.

• Grab the campaign ID in the address bar of your browser.

• See an example in the image below:

Update your Share URL with a ?growsurf_campaign parameter

Step 2: Paste this code into the <HEAD> of your website instead of the GrowSurf Universal Code

Instead of pasting the GrowSurf Universal Code into the <HEAD> of your webpage(s), add the following code below. Make sure to update the DEFAULT_GROWSURF_CAMPAIGN_ID value at line 3 to your own default campaign ID.

<script type="text/javascript">
   // Update these parameters
   const DEFAULT_GROWSURF_CAMPAIGN_ID = 'abc123'; // (Optional) Replace with your default campaign ID. This will be used as a fallback if provided.
   
   // Additional configurable parameters
   const GROWSURF_CAMPAIGN_ID_URL_PARAM = 'growsurf_campaign';
   const GROWSURF_CAMPAIGN_ID_COOKIE_NAME = 'growsurf_campaign'; // Make it the same name as the URL param for simplicity

    function getBaseDomain() {
      const hostname = window.location.hostname;
      const parts = hostname.split('.');
      if (parts.length > 1) { return '.' + parts.slice(-2).join('.'); }
      return hostname;
   }

   function getQueryParam(name) {
      const urlParams = new URLSearchParams(window.location.search);
      const value = urlParams.get(name);
      if (value && value.includes('?')) {
         return value.split('?')[0];
      }
      return value;
   }

   function setCookie(name, value, days) {
      let expires = "";
      if (days) {
         const date = new Date();
         date.setTime(date.getTime() + days * 24 * 60 * 60 * 1000);
         expires = "; expires=" + date.toUTCString();
      }
      const domain = getBaseDomain();
      document.cookie = `${name}=${value}; domain=${domain}; path=/;${expires}`;
   }   

   function getCookie(name) {
      const nameEQ = `${name}=`;
      const ca = document.cookie.split(';');
      for (let i = 0; i < ca.length; i++) {
         let c = ca[i];
         while (c.charAt(0) === ' ') c = c.substring(1, c.length);   
         if (c.indexOf(nameEQ) === 0) return c.substring(nameEQ.length, c.length);
      }
      return null;
   }

   const growsurfCampaignIdInUrlParam = getQueryParam(GROWSURF_CAMPAIGN_ID_URL_PARAM);
   if (growsurfCampaignIdInUrlParam) {
      setCookie(GROWSURF_CAMPAIGN_ID_COOKIE_NAME, growsurfCampaignIdInUrlParam, 365); // Stores campaign ID in cookie for 365 days
   }   
   const growsurfCampaignId = getCookie(GROWSURF_CAMPAIGN_ID_COOKIE_NAME) || DEFAULT_GROWSURF_CAMPAIGN_ID;
   if (growsurfCampaignId) {
      console.log('Loading GrowSurf Universal Code with campaign ID:', growsurfCampaignId);
      // Call the GrowSurf Universal Code
      (function(g,r,s,f){g.grsfSettings={campaignId:growsurfCampaignId,version:"2.0.0"};s=r.getElementsByTagName("head")[0];f=r.createElement("script");f.async=1;f.src="https://app.growsurf.com/growsurf.js"+"?v="+g.grsfSettings.version;f.setAttribute("grsf-campaign", g.grsfSettings.campaignId);!g.grsfInit?s.appendChild(f):"";})(window,document);            
   }
</script>

Here's what this code does:

• Referral links will now look something like this: https://mysite.com?growsurf_campaign=abc123&grsf=xyz789 . The campaign ID is abc123 and will be saved as a cookie for 365 days. So when a referred friend lands on a referral link, the appropriate campaign ID will first be loaded. (The referrer ID xyz789 is also automatically saved as a cookie).

• If that referred friend revisits or returns to your site (e.g, mysite.com) even without using a referral link, the appropriate campaign will still be loaded b/c the campaign ID was saved as a cookie.

• Once the referred friend signs up, the campaign that they originally came through a referral link from will be the one they get added to.

• If a website visitor did not use a referral link to land on your website and sign ups, the fallback campaign abc123 will be the one used.

Example 11: Display a Referral Link on Your Login Page

In this tutorial, you'll learn how to display referral links to users on your login page. The typical use-case for this is to remind returning users of your referral program and conveniently provide their referral link that they can share.

Display a referral link to returning users on your login page

This tutorial uses React, Firebase Authentication, and the GrowSurf JavaScript SDK.

Demo: To view a working demo and to access the full code, click here.

Step 1: Install GrowSurf in Your React App

The first step is to install the GrowSurf Universal Code by dynamically injecting it into your React app.

Inside your App.js, add the following function and use it in a useEffect:

const GROWSURF_CAMPAIGN_ID = "x8yi1l" // Replace with your own campaign ID

const addGrsfScript = () => {
  if (document.querySelector('script[src*="growsurf.js"]')) return;
  const script = document.createElement("script");
  script.src = "https://app.growsurf.com/growsurf.js?v=2.0.0";
  script.setAttribute("grsf-campaign", GROWSURF_CAMPAIGN_ID);
  script.async = true;
  document.head.appendChild(script);
};

useEffect(() => {
  onAuthStateChanged(auth, (user) => {
    setCurrentUser(user);
  });

  if (document.readyState === "complete") {
    addGrsfScript();
  } else {
    window.addEventListener("load", addGrsfScript);
    return () => window.removeEventListener("load", addGrsfScript);
  }
}, []);

Important: Make sure to replace x8yi1l at line 1 with your own campaign ID.

This ensures GrowSurf loads once when the app starts.

Step 2: Register Users and Add Them to GrowSurf

For the purpose of this demo, this is the logic that we'll have when a new user registers:

1. Create the user in Firebase

2. Add the user to GrowSurf using growsurf.addParticipant()
3. Redirect them to the Profile page

This is what the register() function in the Register.js file looks like:

const register = (e) => {
  e.preventDefault();
  createUserWithEmailAndPassword(auth, email, password)
    .then((userCredential) => {
      const user = userCredential.user;
      
      // Add user to GrowSurf
      if (window.growsurf?.addParticipant) {
        window.growsurf.addParticipant(user.email);
      }
      navigate("/"); // Redirect to profile
    })
    .catch((err) => setError(err.message));
};

Step 3: Display Profile Page After Login/Registration

In the Profile.js file, we'll show the user’s email and display a Logout button:

<h2>Welcome, {currentUser.email}</h2>
<button onClick={logout}>Logout</button>

When the user logs out, they’re redirected back to the Login page.

Step 4: Login and Validate the GrowSurf Participant

When a user logs in, we'll have the following logic be executed:

1. After a successful Firebase login, check if the user exists in your GrowSurf campaign using growsurf.getParticipantByEmail(email).
2. If the user exists in the campaign, call growsurf.addParticipant(email) to log them in as a GrowSurf participant.

Here's what we have in the Login.js file:

const login = (e) => {
  e.preventDefault();
  setError("");

  signInWithEmailAndPassword(auth, email, password)
    .then(() => {
      if (window.growsurf?.getParticipantByEmail) {
        window.growsurf.getParticipantByEmail(email, (participant) => {
          if (participant) {
            // Initialize GrowSurf participant session
            window.growsurf.addParticipant(email, () => {
              localStorage.setItem("hasLoggedIn", "true");
              setShowReferral(true);
              navigate("/");
            });
          }
        });
      } else {
        setError("GrowSurf is not ready. Please try again shortly.");
      }
    })
    .catch((err) => setError(err.message));
};

Step 5: Show the Referral Widget (Only After Logout)

After tracking the user login state, we can now conditionally display the GrowSurf Embedded Form (aka the referral link) on the Login page — but only after logout.

{showReferral && (
  <div className="referral-sidebar">
    <div
      data-grsf-block-form
      data-grsf-share-instructions="<h3 style='text-align: center;'>Refer a friend</h3>"
      data-grsf-social-buttons-layout-theme="3"
      data-grsf-copy-link-button-layout-theme="3"
    ></div>
  </div>
)}

Important note on authentication: This tutorial focuses on integrating GrowSurf referral tracking in a React app using Firebase for authentication. However, the same concepts apply no matter what auth system you’re using (Supabase, Auth0, a custom backend, etc).

For simplicity, the tutorial assumes that returning users already exist in both your authentication system and your GrowSurf campaign.

This tutorial doesn’t cover all security details, and you'll want to adapt the logic to fit your own authentication flow and app structure.