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Technique 5.3.3

From: Jon Gunderson <jongund@uiuc.edu>
Date: Wed, 01 Sep 1999 11:00:49 -0700
Message-Id: <4.1.19990901105730.00ca5970@staff.uiuc.edu>
To: w3c-wai-ua@w3.org
I have attached a HTML file for techniques for alternatative alrogithms for
assuming headers in 5.5.3 of the techniques document: The HTML source
follows:  

5.3.3 Cell header algorithm


Header information is available from the document source


User agents should use the algorithm to calculate header information provided
in the HTML 4.0 specification ([HTML40], section 11.4.3). 

[Ed. The following issues were raised by Harvey Bingham.] 
    * TH cells on both the left and right of the table need to be considered.  
    * For TH cells with "rowspan" set: the content of those TH cells must be
    considered for each of the N-1 rows below the one containing that TH
    content.  
    * An internal TH in a row surrounded on either side by TDs has no means to
    specify to which (row or column) that TH overrides what existed to its left
    or above it.  
    * Finding column header cells assumes they are all above the TD cell to
    which they apply.  
    * A TH with "colspan" set needs to be included in the list of TH for
the M-1
    columns to the right of the column in which the TH is found. 

[Ed. The following issues were raised by Jon Gunderson]
    * Multiple rows or columns of header cells  

Example: 

 

TH Information is not available from the document source


If an author of a data table does not supply information about which cells in
the table are the headers by using either the TH element or using the SCOPE
attribute, the user agent should allow the user to make assumptions about which
cells in the table are being used for header information. By assuming header
cells a table can be made more understandable when using speech or refreshable
Braille displays. The user should be oriented to the problem and be able to
choose the algorithm used to determine which cells are header cells.

First Column


First row algorithm:

1. Find the right most cell in the current row and include row span cells in
the right most search.

2. Find the top most cell of a column and include column span cells in the
search

3. A clue to using the first row assumption would be to check the first cell in
every row has content and that the number of data elements is the same in each
row.

Example: The following table is an example of a table where the first row could
be used as header cells. The first data cell would be assumed to a data cell
would be the cell in the second row and first column. It could be rendered
through a speech synthesizer as "Issue number sign 3".
Open Issues  
Issue # Name Description Date Type Resolution First Working Draft Comments and
Reference URLs  
3 Al Gilman
<http://lists.w3.org/Archives/Public/w3c-wai-gl/1999JanMar/0521.html>What
should
UAs do with recognize navigation bars? Mon Apr 19 17:15:04 1999 Checkpoints Not
resolved No reference 
<http://cmos-eng.rehab.uiuc.edu/ua-issues/issue0003-comments.html>Comments and
Key References  
34 Jon Gunderson
<http://www.w3.org/WAI/UA/1999/02/wai-ua-telecon-19990203.html>Allow the user
to view assumed headers associated with a cell Tue Apr 20 17:17:25 1999
Checkpoints Not resolved No reference 
<http://cmos-eng.rehab.uiuc.edu/ua-issues/issue0034-comments.html>Comments   
40 Denis Anson
<http://lists.w3.org/Archives/Public/w3c-wai-ua/1999AprJun/0064.html>What types
of navigation commands support visually impaired users navigating a unfamilar
document? Wed Apr 28 17:23:36 1999 Issue Not resolved No reference  None   

First column and first row


First row and first column algorithm:

1. Find the right most cell in the current row and include row span cells in
the right most search.

2. Find the top most cell of a column and include column span cells in the
search

3. A clue to using the first row and first column assumption would be to check
the first cell as an empty cell.

Example: The following table does not indicate which cells are header cells in
the markup. The header cells though are clearly the first row and first column.
The first data cell would be assumed to a data cell would be the cell in the
second row and column. It could be rendered through a speech synthesizer as "hp
omni book cpu speed intel 400-, 366-, 333-, or 300 mhz mobile pentium i i
processor"
   HP OmniBook 
4150 Series  HP OmniBook 
900 Series  HP OmniBook 
XE2 Series  
 

CPU Speed 
 

Intel 400-, 366-, 333-, or 300-MHz Mobile Pentium II processor
 

Intel 400-, 366- or 300PE-MHz Mobile Pentium II processor
 

Intel 366-, 333- or 300PE-MHz Mobile Pentium II or 333- or 300-MHz Mobile
Celeron processor 
 

Cahce
 

512-KB pipeline-burst asynchronous L2 cache (for 300-MHz models) 256-KB
on-board 4-way set-associative L2 cache (for 400-, 366- and 333-MHz models) and
32-KB internal L1 cache
 

256-KB on-board 4-way set-associative L2 cache and 32-KB internal L1 cache
 

256- or 128-KB embedded pipeline-burst synchronous L2 cache and 32-KB internal
L1 cache
 

Memory
 

128 or 64 MB of SDRAM standard; expandable to 256 MB
 

32 MB standard; expandable to 160 MB
 

64 or 32 MB of SDRAM standard; expandable to 256 MB
 

Mass 
Storage
 

10.1-billion-byte (9.41-GB) or 6.4-billion-byte (5.96-GB) or 4.8-billion-byte
(5.96-GB) removable Enhanced-IDE hard drive; 3.5-inch, 1.44-MB floppy disk
drive module; optional 24X-maximum-speed CD-ROM drive, LS-120 SuperDisk, 4X
DVD-ROM3 drive, and second 6.4-billion-byte hard disk drive modules
 

6.4-billion-byte (5.96-GB) or 4.3-billion-byte (4.01-GB) removable Enhanced-IDE
hard drive; 3.5-inch, 1.44-MB floppy disk drive module; optional
24X-maximum-speed CD-ROM drive, LS-120 SuperDisk, 4X DVD-ROM drive, and second
10.1-billion-byte (9.41-GB) hard disk drive modules
 

6.26-billion-byte (5.83-GB) or 4.1-billion-byte (3.82-GB) removable
Enhanced-IDE hard drive; built-in, 3.5-inch, 1.44-MB floppy disk drive;
built-in 24X-maximum-speed CD-ROM drive
 

Display
 

14.1" 102x768 XGA TFT with 16 million colors
 

12.1" 800x600 SVGA TFT display with 16 million colors
 

13.3" diagonal 1024x768 XGA TFT display with 65,536 colors or 12.1" diagonal
800x600 SVGA HPA or TFT display with 16 million colors4


Received on Wednesday, 1 September 1999 11:56:04 GMT

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