- From: Robert Burns <rob@robburns.com>
- Date: Wed, 15 Aug 2007 03:25:43 -0500
- To: Robert Burns <rob@robburns.com>
- Cc: HTML WG <public-html@w3.org>
Hello all, For an real-world example table that could benefit greatly from fixed thead, tfoot, tlead and ttrail elements, see all of the tables after the heading "Details" on this page: <http://www.w3.org/2002/09/wbs/40318/tasks83/results> The idea as outlined in HTML 4.01 and RFC 2854, is that, in these tables, the first column and row would remain fixed and the table bodies (as a single unit) would be presented with horizontal and vertical scrollers. Without these features these tables are inaccessible to almost everyone :-). I'm venting a bit since I don't know if I've ever seen an example table that needed these features so bad. However, I'm also serious. These do make great real-world usse- case examples of why we need these features. Take care, Rob Original message ------- On Aug 10, 2007, at 2:31 AM, Robert Burns wrote: > > table, DOM interfaces, cell, heading, leader, trailer, header, > footer, runner, TABLE, CAPTION, COLGROUP, COL, THEAD, TFOOT, TR, > part of my review of 3.15 Tabular data > Re:<http://dev.w3.org/cvsweb/~checkout~/html5/spec/Overview.html? > rev=1.78#tabular> > > SUMMARY > -------------------------------- > • consider restoring heading related and other table cell > attributes to HTML: @abbr, @headers, @scope, @axis, > • consider adding lateral runners TLEAD, TTRAIL, TC (column) > elements to the TABLE content model > • consider adding a @kind attribute to the TD element to indicate > whether the cell is a 'heading' cell, a 'summary' cell, or 'neither'. > > > HTML 4.01 table attributes > -------------------------------- > > To continue to allow authors the same level of expressiveness in > creating tables, we need to add the HTML 4.01 table attributes to > HTML5. Without these attributes, HTML5 would constitute a regress > in terms of table semantics. > > @headers, has been relied upon by authors and aural UAs to provide > the information necessary to associate data cells and header cells. > However, leaving such misuse aside (which we should deprecate even > while retaining @headers in document conformance norms), the > @headers attribute is an important attribute to associate data > cells with header cells in more complex tables. In many cases > @headers can provide a shortcut for associating cells when compared > to @scope. > > The @abbr attribute provides functionality for HTML 4.01 > conforming documents that cannot be achieved with an HTML5 > conforming document. There may be an easier or better way to > abbreviate headings (including having UAs rely on UA abbreviation > dictionaries), however authors may still need to provide > abbreviated headings when no such dictionary entry exists. > > While the @scope attribute is included on the TH element in the > current HTML5 draft, it has been removed from the TD element. The > use of @scope on the TD element is important to be able to make a > data cell behave as a heading for other data cells. The existence > of a @scope attribute on a TD element indicates that the data cell > contains a heading for other data cells. It may even be useful to > allow an explicit value for @scope of 'auto' or 'all' to indicate > a data cell contains a heading, but should not have its scope reduced. > > The @axis attribute allows authors to designate dimensions beyond > the natural two dimensions available on a table. For some > relatively complex data, the use of an axis can vastly simplify the > visual presentation of the data when compared to other approaches. > > All of these attributes address well known use-cases as outlined in > the HTML 4.01 recommendation [1]. It is important to start from use- > cases and problem statements before proposing sweeping changes to > the web like this. In order to remove these attributes it is > therefore important for us to discuss the problem-statement that is > being addressed by removing these attributes. In other words, what > problem will removing something like @headers solve? > > Lateral runners: TLEAD and TTRAIL > ----------------------------------------------- > > THEAD and TFOOT are intended as column global headings and column > global summaries: appearing fixed and available for visual review > while scrolling the table bodies. The rows currently offer no > similar mechanism. To allow tables to work in a more symmetrical > way, consider adding table leader (TLEAD ) and table trailer > (TTRAIL) elements. These would be lateral runners and work in a > similar way to the already existing top and bottom runners, THEAD > and TFOOT. However, these elements would comprise columns rather > than rows., so we should consider adding a content model too TLEAD > and TTRAIL of one or more TC table column elements. The TC element > content model would be the same as a TR. However, the arrangement > of cells within the TC would be vertically stacked cells rather > than horizontally arranged cells. The TTRAIL and TLEAD elements > would constitute their own column groups: and would have the same > number of rows (TD and TH cells) as the table body or table bodies > taken together (or implied if the number of rows in the table > exceeded the number of cell in the TLEAD or TTRAIL). > > Table summary cell > -------------------------------- > > To provide a way of marking a cell as a table summary cell, > consider adding an boolean attribute @summary. It may even be > useful to add a @kind or @type attribute to TD cells to be able to > mark them as either headings or summaries (i.e., kind=''heading' or > kind='summary'). Setting a cell to be a summary cell would have a > corresponding algorithm like the headers association algorithm but > working in the opposite direction (up and to the left rather than > down and to the right). > > Summing up > -------------------------------- > > these proposals are to round out the expressiveness of tHTML. The > newly proposed elements would be incompatible with existing UAs in > the text/html serialization. They might be more likely to degrade > gracefully within the XML serialization, ,however non-HTML5 UAs > would not know how to present them. CSS also does not support the > lateral runner concepts proposed in this review, so its table model > would have to be updated to support those runners. However, CSS > also needs enhancement to handle the existing THEAD and TFOOT > runners, as authors may want to provide fixed THEAD and TFOOT with > the main body of the table presented in a fixed frame with overflow > and clip control through scrollers. I do not believe this level of > control is available now with CSS or proposed with CSS3 even for > the existing table runners. elements with scrolling table bodies. > So adding lateral runner support to CSS could occur at the same > time CSS is enhanced to support top and bottom runners. > > [1]: HTML 4.01 Chapter 11: Tables <http://www.w3.org/TR/html4/ > struct/tables.html#h-11.3.2.1> >
Received on Wednesday, 15 August 2007 08:25:57 UTC