How to set up Load External Scripts Asynchronously?

One of my plugin sync my product to facebook, but I do not need it at home page.
The facebook is banned in China, some of my visitors are continuing waiting for TTL to facebook.
I see your plug can set up External Scripts Asynchronously.
When I set it to ‘on’, it ask me to fill Set external scripts urls to load:

The link is https://connect.facebook.net/en_US/fbevents.js

What should I fill into ‘Set external scripts urls to load:’?
https://connect.facebook.net/en_US/fbevents.js or connect.facebook.net/en_US/fbevents.js