Element.getBoundingClientRect() and Element.getClientRects() do not take scrolling into account.

[peterjoel]

Related to #9650.
These rectangles should be translated by scrollTop and scrollLeft.

Spec: https://drafts.csswg.org/cssom-view/#dom-element-getclientrects

[jdm]

@peterjoel Can you link to the part of the specification that suggests that they should?

[peterjoel]

I was just going by the behaviour in Safari, Firefox and Chrome. The spec isn't incredibly clear, but it says:

Apply the transforms that apply to the element and its ancestors.

If you follow the link on "transforms" and keep following the linked documents to this, you find:

current transformation matrix (CTM)
A matrix that defines the mapping from the local coordinate system into the viewport coordinate system.

Which seems to suggest that the transformations are relative to the viewport, not the document.