I have a js file that specifies css edits to a page I am iframing. The iframed page is an external site that I don't own. The owner has installed a google tag manager container to the external page and I just need to add the script the plugin I asked for help with before advanced iframe pro has a workaround to add a script <script src="http://mywebsite/wp-content/plugins/advanced-iframe/js/ai_external.js"></script>
that calls back to the js file. I don't know which configuration to use in tag manager to execute this call back. Can you help me determine which of these configurations I should use
1st Party Cookie
The value is set to the first value of the 1st party cookie with the matching name.
Data Layer Variable