They are used to define groups of columns within a table.
<colgroup> defines the total group of columns and
<col> defines each of the columns in the group. It is useful for applying styles to entire columns, rather than repeating them for cells and in each row.
<colgroup> must be a child of a
<table> element, after
<caption> and before
<th>. It has a
span attribute, which will contain a positive integer indicating the number of consecutive columns it spans. If not present, its default value is
1. This attribute cannot be used if the
<colgroup> contains one or more
<col> has to be a child of a
<colgroup> element. Like its parent, it has a
span attribute that will contain a positive integer indicating the number of consecutive columns it spans. If it is not present, its default value is
- Type: table-column-group / table-column
- Self-closing: No / No
- Semantic value: No / No