How to track changes on a web page?

Question

Browsers

Hi all.
I have a Mozilla browser.
It has a page open. It is made up of frames.
One of the frames constantly says "No trades".
But sometimes, the page is updated and a new deal is written.
It must be accepted or canceled, that's not the point. I will do this by hand.
How can I get some kind of sound notification that the page (frame) has changed?
I don't want to change my browser.

Answer 1

https://habrahabr.ru/post/202366/ - ???