$(document).scrollTop() always returns 0

For some reason, removing 'height: 100%' from my html and body tags fixed this issue.

I hope this helps someone else!

I had same problem with scroll = 0 in:

document.body.scrollTop

Next time use

document.scrollingElement.scrollTop

Edit 01.06.2018

If you using event then you got object which has document element in target or srcElement. Here is a table showing scroll operation on different browsers.

As you can see Firefox and IE doesn't have srcElement and IE 11 doesn't support scrollingElement.

My solution, after trying some of the above and which doesn't involve changing any CSS:

var scroll_top = Math.max( $("html").scrollTop(), $("body").scrollTop() )

This works in up-to-date versions of Chrome, Firefox, IE and Edge.