What's the advantages of external JS over the one included in HTML file?

Answer 1

A script written in an external document.js can be called and used in many html pages, without copying it in every single html files.

Answer 2

It's simply that it separates the code and the actual text.
Makes it better to understand.
And most important- When we are using the same code again and again, it is better to place the code externally.

Answer 3

external js makes code easy to read