Did they tell you which page they want this on? I would think the order confirmation or checkout_success page would be it, but you need direction from them. In any case, you would not paste the code into any PHP file; you would rename them to start with jscript_ and save them in one of the /jscript/ folders, depending on what page they are needed in. The /jscript/ folders for a template or page will autoload all files that start with jscript_.
jscript_shopzilla_data.js
(do not include <script> tags in this file)
Code:
<!--
/* Performance Tracking Data */
var mid = '';
var cust_type = '';
var order_value = '';
var order_id = '';
var units_ordered = '';
//-->
jscript_shopzilla_tracker.js
Code:
<script language="javascript" src="https://www.shopzilla. com/css/roi_tracker.js"></
script>
I'm not certain of the way to call an external script in this format, so anyone with authoritative info, please chime in.
You also need to get the current order info into the script variables, which is another task. You might need to name the file jscript_shopzilla_data.php and include some PHP code to insert the variables.