I've been told this could be done with the Magic module but I couldn't find documentation\videos\readme anywhere for it so I ask how to do these specific things with it in my Drupal 7 site:
- How to make JS Async?
- How to eliminate unnecessary JS?
I need this for trying to take care the known Page spped insights advice "Eliminate render blocking JS above the fold content". Thanks.
Update: This could be done with AdvAgg module easily, see the following answer by Mikeytown2: