HTML : How can I save and restore Selection range in javascript?

HTML : How can I save and restore Selection range in javascript?
To Access My Live Chat Page,
On Google, Search for "hows tech developer connect"

As promised, I have a secret feature that I want to reveal to you.
This is a YouTube's feature which works on Desktop.
First, Make sure the video is currently in playing mode.
After that, type the word 'awesome' on your keyboard.
It will change your youtube progress bar into a flashing rainbow.

Allow me to introduce myself briefly,
Greetings, my name is Delphi.
I am at your disposal to help you with any questions you have.
HTML : How can I save and restore Selection range in javascript?
I welcome your comments and chats if you have more detailed queries.
Please feel free to share your answer or insights on the answer by leaving a comment below.
I will 'heart' your answer as a sign of appreciation.
How in I and can Selection HTML range : save restore javascript?