[WSG] Questions about Data Tables and Accessibility
Hehehe I found something productive to do! For a Good While Now I have been covering my eyes with my hands and singing la la la at the top of my lungs to avoid the fact I don't really know how to construct accessible data tables. So I sat down with an old data table that has another nested, and tried to make that more semantic. Despite researching things, I still have a few questions (some are easier than others) : 1. when abbreviating number to no. does the period belong within the abbreviation element? eg. abbr title=numberno./abbr or abbr title=numberno/abbr. 2. How to tell when one table or two tables is better? When is it better to split up the data? What happens if you have two columns with the same name? Is this bad table structure? I have two colgroups that contain the same information, just placing the information in different units. Should I split that into one table for one unit, and another table for the next unit? 3. Are colgroups only for presentation or is there some way to use them to demarcate which data has closer relationships? Are there ids, headers or something involved? How is it done? Is there some sort of way that someone using the accessibility features can choose one or other colgroup? 4. In what order do headers go on table cell data? Does this matter? 5. Does it cause difficulty if you snub a caption because the table is the main (only) element in the page, and thus what would be the table caption really belongs in the level 1 heading? 6. If you have a table-header that spans two rows - is it seen as the table header for both rows? This would mean that there would be a double-up with table cells having the same headers. The data is correct because both sets of data in each row do apply to that particular table header. How do I put that in a straightforwards fashion to reduce the odds of confusing someone using the accessibility features? For example: thead tr thHeadings/th thA/th thB/th thC/th /tr /thead tbody tr td rowspan=2 scope=rowTable Row Header/td tdData 1a/td tdData 1b/td tdData 1c/td /tr tr tdData 2a/td tdData 2b/td tdData 2c/td /tr /tbody 7. What is the best thing to do? To place scope or headers, or scope and headers? I will appreciate any questions answered, Thank you :) Kat ** The discussion list for http://webstandardsgroup.org/ See http://webstandardsgroup.org/mail/guidelines.cfm for some hints on posting to the list getting help **
Re: [WSG] Questions about Data Tables and Accessibility
Well, I can't answer all of your questions, but I'll do what I can to get the ball rolling. :) 2. How to tell when one table or two tables is better? When is it better to split up the data? What happens if you have two columns with the same name? Is this badtable structure? I have two colgroups that contain the same information, just placing the information in different units. Should I split that into one table for one unit, and another table for the next unit? Would it make sense to give them each a different heading, for example: width (cm) and width (in)? Not exactly sure what your requirements are, or even exactly what your data is or is about, but it is something to consider. I think seperate tables is probably overkill, especially if there's a lot of other information in the table that would simple be duplicated. 3. Are colgroups only for presentation or is there some way to use them to demarcate which data has closer relationships? Are there ids, headers or something involved? How is it done? Is there some sort of way that someone using theaccessibility features can choose one or other colgroup? I believe they do help accessibility in the way you're describing, but I'm not entirely sure of the technicailities of it. But, for example, if you split your two columns mentioned above into seperate headers, it might make sense to put them in a colgroup together. 4. In what order do headers go on table cell data?Does this matter? Not entirely sure what you mean here. Do you mean how they are read by a screen reader? 7. What is the best thing to do? To place scope or headers, or scope andheaders? I favour scope and headers. It's mainly for the use of screen readers, since I believe most of them will: a) use a different inflection or otherwise make it obvious when something is a header rather than just data, and b) alter the way they read the table based on the header's scope. So it's a way of making a large and complex table much easier to follow for someone who can't see the physical relationships between each cell. Hope this helps a little. Cheers, Seona.
Re: [WSG] Questions about Data Tables and Accessibility
Hi Kat, I'll paraphrase while attempting to answer abbreviation for number? abbr title=numberno./abbr When is two tables better than one? When you have a logical grouping that shares some attributes, but the data makes sense when presented as a stand-alone table. When is it better to split up the data? When you have an 'excessive' number of rows or columns. Is two columns with the same name bad table structure? Possibly, but there must be some feature of each of the columns that makes them distinct from each other. If so, include the distinguishing feature as part of the column heading. Should I split a table on units? Not neccessarily, just insure that the unit forms part of the column label. Are colgroups only for presentation? colgroup is structural, col is presentational. Using them demarcates data. Are there ids, headers or something involved? Not for colgroups How is it done? Is there some sort of way that someone using the accessibility features can choose one or other colgroup? Add the colgroup element to the top of your table after the caption and before any row groups. In what order do headers go on table cell data? Does this matter? I don't understand the question. Can you omit the caption if the table is the only thing on the page? You really should have a caption. It gets read as part of the table, whereas the heading doesn't. If you have a table-header that spans two rows - is it seen as the table header for both rows? I read somewhere that you shouldn't span rows, but I can't find the source. Anyone? Oh, here is one source but it's not the one I am thinking of http://www.webaim.org/techniques/tables/2 (see 2.7 Avoid spanning rows). There is also an argument around about how it becomes more confusing when a table is linearized. I say avoid rowspan if at all possible. scope, or id and headers? Scope should suffice on simple tables (two or less heading levels, small number of cols and/or rows), complex tables need headers and ids to work well for the widest number of screen readers. HTH kind regards Terrence Wood. ** The discussion list for http://webstandardsgroup.org/ See http://webstandardsgroup.org/mail/guidelines.cfm for some hints on posting to the list getting help **
