19149 – A position fixed node's offsetParent should return null

Bug 19149 - A position fixed node's offsetParent should return null

Summary: A position fixed node's offsetParent should return null

Status:	RESOLVED FIXED

Alias:	None

Product:	WebKit
Classification:	Unclassified
Component:	DOM (show other bugs)
Version:	525.x (Safari 3.1)
Hardware:	PC Windows XP

Importance:	P2 Normal
Assignee:	Nobody

URL:	http://www.gtalbot.org/BrowserBugsSec...
Keywords:	InRadar

Depends on:
Blocks:

Reported:	2008-05-20 12:11 PDT by Gérard Talbot
Modified:	2009-06-14 11:56 PDT (History)
CC List:	3 users (show)

See Also:

Attachments
Fix for offsetParent, offsetTop, and offsetLeft (6.14 KB, patch) 2009-01-17 17:08 PST, Matt Pennig	pennig: review-	Details \| Formatted Diff \| Diff
Fix for offsetParent, offsetTop, and offsetLeft (6.12 KB, patch) 2009-01-18 09:47 PST, Matt Pennig	pennig: review-	Details \| Formatted Diff \| Diff
Show Obsolete (1) View All Add an attachment (proposed patch, testcase, etc.)

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Description Gérard Talbot 2008-05-20 12:11:22 PDT

CSSOM View Module, offsetParent attribute clearly states that 
offsetParent of nodeA when nodeA is a position: fixed element should return
null.

"
If any of the following holds true return null and stop this algorithm:
(...)
    The computed value of the position property for element A is fixed. 
"
http://www.w3.org/TR/cssom-view/#offset-attributes

Steps to reproduce:
1- Load provided URL
2- Click the [return document.getElementById("PositionFixedElem").offsetParent]
button

Actual results in Safari 3.1.1 build 525.17.0 under XP Pro SP3:
document.getElementById("PositionFixedElem").offsetParent = [object
HTMLBodyElement]

Expected results:
document.getElementById("PositionFixedElem").offsetParent = null

Notes:
- Internet Explorer 7, Internet Explorer 8 beta 1 and Opera 9.50 will return
null.
- I have filed a similar bug at
https://bugzilla.mozilla.org/show_bug.cgi?id=434678

I have searched for a duplicate and did not find one. 
I have not checked the testcase with a webkit trunk nightly build (526+).

Comment 1 steven.moore 2009-01-14 10:48:43 PST

I'm seeing this too. WebKit nightly from 13 Jan 2009, OS X 10.5.6.

Comment 2 Matt Pennig 2009-01-15 07:44:24 PST

<rdar://problem/6497927>

Comment 3 Matt Pennig 2009-01-17 17:08:35 PST

Created attachment 26829 [details]
Fix for offsetParent, offsetTop, and offsetLeft

Comment 4 Matt Pennig 2009-01-18 09:47:46 PST

Created attachment 26834 [details]
Fix for offsetParent, offsetTop, and offsetLeft

Comment 5 Anthony Ricaud 2009-02-23 14:26:10 PST

The testcase is working on my nightly (r41121). I've bisected it between r40738 and r40771. http://trac.webkit.org/changeset/40769 may be the revision responsible (I don't understand the patch but it has offsetParent in the summary).

Bug 24097 was fixed as a regression because of this change. One of them is therefore invalid.

Comment 6 Matt Pennig 2009-02-27 12:05:47 PST

This bug was fixed in changeset http://trac.webkit.org/changeset/40769 but there were no tests to make sure that offsetParent of a fixed element was null. Bug 24107 fixes a related issue caused by the above changeset. In the included patch, there are a number of tests which have coverage on this bug.

Comment 7 Gérard Talbot 2009-06-14 11:56:51 PDT

When I try the provided testcase with latest stable release Safari 4.0 build 530.17, I get expected results.

Resolving as FIXED

Thank you Matt!

regards, Gérard