How can you do that?

Once you have the element, you can inspect its scrollLeft and scrollTop properties.

The 0, 0 position is always found in the top left corner, so any scrolling is relative to that.

Example:

const container = document.querySelector('. container')
container.scrollTop
container.scrollLeft

Those properties are read/write, so you can also set the scroll position:

const container = document.querySelector('. container')
container.scrollTop = 1000
container.scrollLeft = 1000