Omni Systems, Inc. Mif2Go User's Guide, Version 55
> 27 Marking HTML table cells for WAI > 27.5 Using ColGroup and RowGroup cells > 27.5.1 Understanding how the ColGroup property works
When you designate a header cell as a ColGroup cell, the effect of that property on the table depends on which accessibility method you have specified:
Using the scope
method
automatically specifies ColGroupElements=Yes
;
the ColGroup cell starts a new <colgroup>
element; and the ColGroup
cell’s information applies to all cells subsumed by that element.
ColGroupElements=Yes
is a necessary condition for scope="colgroup"
,
but not for id/headers="groupN"
; for the latter,
the ColGroupElements
value does not affect
which cells are marked id/headers="groupN"
.
ColGroupIDs=Yes
is
a necessary condition for id/headers="groupN"
,
but not for scope="colgroup"
; for the latter,
the ColGroupIDs
value does not affect which
cells are subsumed under scope="colgroup"
.
Table 27
Table 27
* Set via CellScope
marker or |
|||||||||
If ColGroupElements=Yes
,
each ColGroup cell starts a new <colgroup>
element. If the ColGroup cell contains a CellScope
marker (or the [HTMLParaStyles]/[StyleCellScope]
equivalent) that sets the scope="colgroup"
attribute, the ColGroup property works in concert with the scope
attribute to apply the ColGroup header to all cells subsumed by its <colgroup>
.
The scope
attribute is in effect only within
the same <colgroup>
section as the ColGroup
cell. See §27.2 Using the scope method to identify table cells.
If ColGroupIDs=Yes
,
each ColGroup cell gets an id="groupN"
attribute;
cells below the header cell and to the right of the header-cell column,
across to the next ColGroup header cell or to the edge of the table (see
Figure 27headers="groupN"
attribute.
If ColGroupElements=Yes
, these are the cells
subsumed by the <colgroup>
element.
See §27.3.3 Grouping header cells for identification.