Hi Emily,
To pass back a data element to a third party tag, you can use use the below snippet of code in the Third party/ Javascript tab.
<script id="id1" src="" type="text/javascript"></script> <script type="text/javascript"> (function(){ var str= "https://smrtpxl.advertising.com/S?spid=215&ORD="; var val=_satellite.getVar('dl.purchaseID'); str.concat(val); document.getElementById("id1").src= str; }());</script>
Please do let us know if you have any questions or queries
Thanks & Regards
Parit Mittal