scroll up and down buttons

Add up/down navigation buttons with a settings panel (timer & transparency).

this is a very helpful userscript that allows you to scroll to the top and bottom of a web page.

Marjanoo edition - where you have the option to make the button transparent (so that the buttons won't get in the way):
https://greasyforks.org/en/scripts/546045-scroll-up-and-down-buttons?version=1664766

if the current version of the script doesn't show its buttons, please use the marjanoo version as that version doesn't have this issue