Web Accessibility: Tables and Forms

There's something that has puzzled me for a while now.

Why do some people regard as a data table a table that is used to control the visual layout of a form? These aren't dumb people, or people who don't know very much about web accessibility. In some cases they're people whose knowledge of web accessibility I respect. But I do disagree with them on this issue.

The working definition I use to decide if an HTML table is a layout table or a data table is this (assume the table is structured correctly, whichever kind of table it is):

1. Does the content of the table make sense when the table structure is removed and the content is presented in a linear fashion?
   If the answer to this is "yes", it's most likely a layout table.


2. Is the table structure essential to understanding the content of the table, so that much of the meaning is lost when that structure is removed?
   If the answer to this is "yes", it's most likely a data table.

So far, I haven't come across any situations where these two questions don't give a clear indication as to whether the HTML table I'm reviewing is a layout table or a data table.

Using these two questions when reviewing a table which contains a form, the clear answer, it seems to me, is that the content still very much makes sense when the table structure is removed, and that the table is there purely for the purpose of controlling the visual layout of the form elements. It isn't required in order to be able to read, understand or use the form.

HTML markup for forms provides perfectly adequate facilities for structuring the form content, and making clear the relationship between, for example, a text label and the form control to which it relates. The table structure isn't needed for this. A form which is not contained in a table might look untidy (unless CSS formatting is used instead), but it isn't less meaningful, or more difficult to understand and use, than the same form presented in a table.

So why do some feel that a form needs a table and/or that a table which contains a form is a data table?

Technorati: Accessibility, Web Accessibility, Web Standards