Hans Hillen Reporter
	Description • 10 years ago

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36

Steps to reproduce:

When a table has a caption element that is styled with position:absolute, NVDA will treat it as a row when calculating the total number of rows in the table. A common use case for using absolute positioning is when the caption should be hidden visually but not from assistive technology.

I have attached a ​test case that illustrates this. The page contains two tables with identical content, except that in the second table the caption text is hidden off screen using CSS. When pressing the T key twice, NVDA will correctly announce 4 rows for the first table and incorrectly 5 rows for the second table.

Originally this bug was filed with NVDA (http://community.nvda-project.org/ticket/3813), but they mentioned that it's actually Firefox exposing the tables as having 5 rows. They also suggested that Firefox probably has some logic that normally excludes the caption from the row count, and that this logic breaks when the caption is absolutely positioned. Looking in DOM Inspector I can see that the the absolutely positioned caption is not exposed as an accessible object, while the first one is. This seems to be the cause of this issue. 



Expected results:

The caption should be exposes as an accessible object regardless of how it's positioned, an the correct rowcount should be exposed

	Marco Zehe (:MarcoZ)
	Comment 1 • 10 years ago

Confirmed also in 31 nightly.

	alexander :surkov (:asurkov)
	Comment 2 • 10 years ago

HTML caption doesn't get an accessible object. I think bug is similar to bug 996821. Anybody is willing to take it?

	Boris Zbarsky [:bzbarsky]
	Comment 3 • 9 years ago

Note that when a caption is absolutely positioned it stops being a caption from the point of view of CSS.  Specifically, it is no longer display:table-caption; it's just a block child of the table, and it (or rather its placeholder) does in fact get an anonymous table cell and table row wrapping it.

So it's not quite clear to me what the right way to expose such a "caption" is, exactly...  

Also, what should happen for non-absolutely-positioned captions that have been styled with a display value other than table-caption?

	Sina Bahram
	Comment 4 • 9 years ago

I filed bug #1201795, which is related to this issue, but has the more frustrating side effect of preventing NVDA from being able to continue past the header with row nav. This then forces the user to navigate to a further row before being able to resume using row nav.

	Marco Zehe (:MarcoZ)
	Comment 5 • 9 years ago

These are probably closely related, so NI'ing Surkov here as well.

	alexander :surkov (:asurkov)
	Comment 6 • 9 years ago

we could expose caption accessible but table interface would be 'broken' anyway per Boris's comment.

	James Teh [:Jamie]
	Comment 7 • 6 years ago

This is being tracked by NVDA as well: https://github.com/nvaccess/nvda/issues/3813
There are pings on that issue from time to time.