How to scroll a dynamically loaded page to the bottom?

Question

JavaScript

I want to display a list of members of a large group on FB, which I moderate.
In a smaller group, I do it manually like this: I scroll the list to the end, copy it to the clipboard, paste it into Excel.
The same group is too large for such manual work.
You put a weight on the space bar and the page starts scrolling.
This takes a lot of time.
If the list were just placed in a large div, it would be possible to scroll to a known larger number in the Chrome console, like this:

var block = document.getElementById("id");
block.scrollTop = 9999;

In the case of a dynamically loaded page, this number does not work.
Maybe there are ideas how to solve the problem?
PS The question is that the resources of the computer may not be enough to display a list of this size, etc., I leave behind the scenes.