Javascript: Does modifying scrollTop/scrollLeft trigger browser reflow?

Question

I'm wondering if animating the scrollbars with Javascript triggers browser reflow.

Any difference across different browser implementations?

window.pageXOffset & window.pageYOffset
document.documentElement.scrollLeft & document.documentElement.scrollTop
document.body.scrollLeft & document.body.scrollTop

Thanks!

Answer 1

I dug in deeper and found this link which says it does cause reflow: http://www.phpied.com/rendering-repaint-reflowrelayout-restyle/

I also tested it and modifying scrollTop and scrollLeft both trigger reflow (in Firefox at least).

Heh sorry for answering my own question, but hopefully this info is useful for someone :).

Answer 2

According to this question, no.