Bug 218117

Summary:	MouseEvent.offsetX/Y returns wrong value for inline elements
Product:	WebKit	Reporter:	Noam Rosenthal <noam>
Component:	UI Events	Assignee:	Nobody <webkit-unassigned>
Status:	NEW ---
Severity:	Normal	CC:	nige.animal, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified
See Also:	https://bugs.webkit.org/show_bug.cgi?id=271694

Description Noam Rosenthal 2020-10-23 01:13:04 PDT

According to spec (https://drafts.csswg.org/cssom-view/#dom-mouseevent-offsetx), offsetX/offsetY should return the values relative to the element's padding edge.
Firefox does this correctly, WebKit (and also Chromium, currently), return the value relative to the nearest block ancestor. 

See https://codepen.io/noamr-the-selector/pen/WNxRbmZ

Comment 1 Noam Rosenthal 2020-10-23 01:18:56 PDT

Corresponding Chromium bug: https://bugs.chromium.org/p/chromium/issues/detail?id=1141782

Comment 2 Noam Rosenthal 2020-10-23 01:21:01 PDT

Relevant WPT issue: https://github.com/web-platform-tests/wpt/issues/15089

Comment 3 Radar WebKit Bug Importer 2020-10-30 01:13:58 PDT

<rdar://problem/70857665>

Comment 4 Nige White 2022-11-24 01:45:47 PST

This is now fixed on Blink. Safari is the outlier.


This is why we can't have nice things.

We will always need some kind of library to abstract away these browser differences.