.pageYOffset, .scrollY, *.scrollTop always logging undefined

Question

My JS needs to know how far the user is scrolled down the page.

If I run this code:

document.addEventListener('scroll', event => console.log(document.pageYOffset));

...or do the same thing with scrollY ... or scrollTop ... or swap 'document' in for 'window' ... the console hears the event as I scroll, but always logs 'undefined'. This happens across multiple HTML documents, in Chrome and Firefox, whether I have any CSS reset on or not. What am I doing wrong?

these properties are on `window`, not `document` – Robin Zigmond Apr 03 '22 at 15:20 — Robin Zigmond, Apr 03 '22 at 15:20

score -1 · Accepted Answer · answered Apr 03 '22 at 15:23

-1

It's window.pageYOffset not document.pageYOffset. Refer What is the difference between window, screen, and document in JavaScript?

answered Apr 03 '22 at 15:23

HerrAlvé

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*.pageYOffset, *.scrollY, *.scrollTop always logging undefined

1 Answers1

.pageYOffset, .scrollY, *.scrollTop always logging undefined