<colgroup>
Groups columns for shared attributes and lets rendering start before all rows parse.
Baseline: Widely available · Tables
When to use it
After caption, with col children spanning the table's columns.
When not to
It styles columns structurally; per-cell semantics still live on th/td.
Key attributes
span- number of columns when no col children
Example
| Item | Q1 | Q2 |
|---|
<table>
<caption>Two grouped columns</caption>
<colgroup><col><col span='2'></colgroup>
<tr><th scope='col'>Item</th><th scope='col'>Q1</th><th scope='col'>Q2</th></tr>
</table>