I really recommend watching the whole video. But if you don’t have the time for that, I try to give you a summary of the most important points:
- call stack
- event loop
- callback queue
- access to Web APIs offered by the browser
Each of these engines is implemented on its own and has its own pros and cons.
This is explained very nicely at around 12:02 in the video.
You can also check out the presentation by Thomas Hunter if you want to get more information on this topic.
I have to say, this video opened my eyes. And I have a much better understanding now of what goes on under the surface of my browser.