HTML and CSS Reference
<colgroup> . . . </colgroup>
Defines a conceptual group of columns that form a structural division within a table. The col-
group element must appear after the caption element and before any row ( tr ) or row group
( thead , tbody , tfoot ) elements with the table element.
A table may include more than one column group. The number of columns in a group is speci-
fied either by the value of the span attribute or by a tally of column ( col ) elements within the
group. Column groups may be useful in speeding table display (for example, the columns can
be displayed incrementally without waiting for the entire contents of the table) and provide a
system for display on nonvisual display agents such as speech- and Braille-based browsers.
As a child of a table element, after any caption elements and before any thead , tbody ,
tfoot , and tr elements.
If it has a span attribute, then it is empty. If the span attribute is absent, then it should
contain one or more col elements.
The start tag is optional if it has col as its first child and it is not preceded by a colgroup
start tag without an end tag. The end tag is optional if the colgroup is not immediately
followed by a space character or comment. (XHTML: Required/Required.)