Client has a website on Squarespace, with google analytics tracking.
They are using shopify for order processing. I think this is called the 'buy button sales channel' on shopify. When a user clicks 'BUY' on the squarespace site they are forwarded to the shopify domain https://checkout.shopify.com/...
Shopify -> Settings -> Checkout has a field called 'additional scripts' which seems promising. The help states:
The Additional content & scripts box is used to insert code into the template for your order status page. You can add any of the following:
HTML You can use any valid HTML5 code, for example script, style, iframe and object elements.
Liquid code You have access to the checkout and shop liquid objects.
ROI/conversion tracking scripts
Referral tracking scripts
So I added a test script to that field:
<script language="javascript" type="text/javascript">
console.log('test');
</script>
But I don't see any console message. Perhaps this only works on the 'order status page'?