The Criteo OneTag must be installed on the Order Confirmation page of your website regardless of the payment method selected by the user so that you can track the products bought.

Tracking what the user buys allows Criteo to optimize the banner display so that products bought by the user won't be displayed to them again. If you have a different Order Confirmation page for each payment method, make sure the Criteo OneTag is implemented and working on each of those pages.

Transactions outside of your domain

If you offer any payment method where the transaction takes place outside of your domain, (such as PayPal) you may find that a significant number of your customers using that payment method are not being redirected back to your site. If they do not return to the Order Confirmation/Thank You page automatically, you may need to implement the Criteo OneTag on the Pay Now button that redirects to the external domain, so Criteo can capture the transaction.

The example below shows how to implement the Criteo OneTag on a button called "PayPal". There is just one function to be added:

The Criteo OneTag implemented on a button to track external sales

<script type="text/javascript" src="//dynamic.criteo.com/js/ld/ld.js?a=YOUR_PARTNER_ID" async="true"></script>  <script type="text/javascript"> function load_Criteo_OneTag(){ window.criteo_q = window.criteo_q || []; window.criteo_q.push( { event: "setAccount", account: YOUR UNIQUE ACCOUNT ID }, { event: "setSiteType", type: "m FOR MOBILE OR t FOR TABLET OR d FOR DESKTOP" }, { event: "setEmail", email: "TRIMMED AND LOWERCASE USER EMAIL ADDRESS" }, { event: "trackTransaction", id: "TRANSACTION ID", item: [ { id: "FIRST PRODUCT ID", price: FIRST PRODUCT UNIT PRICE, quantity: FIRST PRODUCT QUANTITY }, { id: "SECOND PRODUCT ID", price: SECOND PRODUCT UNIT PRICE, quantity: SECOND PRODUCT QUANTITY } /* add a line for each product in the user's basket */ ]}); } </script>  <button type="button" onclick="load_Criteo_OneTag()">PayPal</button>

How to avoid counting repeated transactions caused by multi-clicks

Sometimes users will double-click the Pay Now button that redirects to the external payment method. To avoid executing the Criteo OneTag each time the user clicks, you can add a variable that prevents the event from being executed more than once.

See the example below:

The Criteo OneTag implemented on a Sales Confirmation page with multi-click detection:

<script type="text/javascript" src="//dynamic.criteo.com/js/ld/ld.js?a=YOUR_PARTNER_ID" async="true"></script>  <script type="text/javascript"> var cto_clicked = false; </script>  <script type="text/javascript"> function load_Criteo_OneTag(){ if (!window.cto_clicked){ window.clicked = true; window.criteo_q = window.criteo_q || []; window.criteo_q.push( { event: "setAccount", account: YOUR UNIQUE ACCOUNT ID }, { event: "setSiteType", type: "m FOR MOBILE OR t FOR TABLET OR d FOR DESKTOP" }, { event: "setEmail", email: "TRIMMED AND LOWERCASE USER EMAIL ADDRESS" }, { event: "trackTransaction", id: "TRANSACTION ID", item: [ { id: "FIRST PRODUCT ID", price: FIRST PRODUCT UNIT PRICE, quantity: FIRST PRODUCT QUANTITY }, { id: "SECOND PRODUCT ID", price: SECOND PRODUCT UNIT PRICE, quantity: SECOND PRODUCT QUANTITY } /* add a line for each product in the user's basket */ ]}); } } </script>  <button type="button" onclick="load_Criteo_OneTag()">PayPal</button>

Generating a random Transaction ID

In the event that the order does not have an associated Transaction ID to pass into the Criteo OneTag when the user clicks on the Pay Now button, you can use this random function to generate one.

Random function:

Math.floor(Math.random()*9999999)

In the example below, this random function is combined with the prefix "Button_" in order to create a Transaction ID that is more easily identified. Where you use multiple payment options you can change the word "Button" for the method selected by the user. For example, if you implemented this code on a button that redirects to PayPal, you can use "PayPal_" instead of "Button_" so it is even easier to identify the transaction.

Note that the code below is just an extract of the trackTransaction event of the Criteo OneTag in order to highlight the portion relating to the Transaction ID.

The Criteo OneTag implemented on a Sales Confirmation page:

 { event: "trackTransaction", id: "PayPal_" + Math.floor(Math.random()*9999999), item: [ { id: "FIRST PRODUCT ID", price: FIRST PRODUCT UNIT PRICE, quantity: FIRST PRODUCT QUANTITY }, { id: "SECOND PRODUCT ID", price: SECOND PRODUCT UNIT PRICE, quantity: SECOND PRODUCT QUANTITY } /* add a line for each product in the user's basket */ ]}); 

Hashing functions