When does JavaScript passes code to browser api so that the code runs asynchronously?

Question

I'm really confused at this event loop, asynchronous stuff of js. Please help.

Answer 1

NEZ answer my question first.

Answer 2

Event loops : https://flaviocopes.com/javascript-event-loop/
Asynchronous JS : https://blog.bitsrc.io/understanding-asynchronous-javascript-the-event-loop-74cd408419ff