One solution would be to create a global page load rule that loads your
external script at, for example, "Page Bottom". In the "JavaScript/Third
Party Tags" section, add a new "Non-Sequential" script. Then use
something like the following to append the library to the page:var
script = document.createElement('script'); script.src =
'http://example.com/js.js'; // your script URL script.onload = function
() { //this is only necessary if you need to call something directly
after the script loads }; ...