The following properties contain how much the window is scrolled:
let t = document.documentElement.scrollTop; // from top
let l = document.documentElement.scrollLeft; // from left
These properties can be changed to scroll the window to an arbitrary position:
document.documentElement.scrollTop = 200;
By clicking on the button, scroll
the window to the position 300px
from the top.
By clicking on the button, scroll
the window to the position 100px
from the bottom.
On button click, scroll the window to the very top.
On button click, scroll the window to the very bottom.