<!ELEMENT colgroup - O (col*)> <!ATTLIST colgroup %attrs; -- id, lang, dir and class -- span NUMBER 1 -- default number of columns in -- -- group -- width CDATA #IMPLIED -- default width for enclosed -- -- COLs -- %cell.halign; -- horizontal alignment in -- -- cells -- %cell.valign; -- vertical alignment in cells -- >
The COLGROUP element acts as a container for a group of columns, and allows you to set default properties for these columns. In the absence of a COLGROUP element, all columns in the table are assumed to belong to a single column group. Each COLGROUP element can contain zero or more COL elements. COLGROUP requires a start tag, but the end tag may be omitted. This is useful when defining a sequence of COLGROUP elements, e.g.
<TABLE FRAME=BOX RULES=COLS> <COLGROUP> <COL WIDTH="1*"> <COL WIDTH="2*"> <COLGROUP> <COL WIDTH="1*"> <COL WIDTH="3*"> <THEAD> <TR> ... </TABLE>
COLGROUP elements can be used with the following attributes:
width=64 width in screen pixels width=0.5* a relative width of 0.5
Relative widths act as constraints on the relative widths of different columns. If a COLGROUP element specifies a relative width of zero, all of the columns in the group should be set to their minimum widths, unless they are associated with a COL element with an overriding WIDTH attribute. When widths are given in absolute units, the user agent can use these to constrain the width of the table. The "*" suffix is used to simplify importing tables from the CALS representation.