A class attribute on a <col> tag assigns one or more classnames to the element.
Classes are used to style elements.
Classnames are defined in a stylesheet or in a local <style> element.
A class attribute styling a <col> element.
| Id | First Name | Last Name | Country |
|---|---|---|---|
| ART-303 | Vincent | Van Gogh | Netherlands |
| ART-877 | Paul | Cézanne | France |
<style>
table.tb { width:100%; border-collapse: collapse; }
.tb th, .tb td { padding:3px; border: 1px solid #777; }
.mint { background-color: mintcream; }
</style>
<table class="tb">
<colgroup>
<col class="mint">
<col span="3">
</colgroup>
<tr>
<th>Id</th>
<th>First Name</th>
<th>Last Name</th>
<th>Country</th>
</tr>
<tr>
<td>ART-303</td>
<td>Vincent</td>
<td>Van Gogh</td>
<td>Netherlands</td>
</tr>
<tr>
<td>ART-877</td>
<td>Paul</td>
<td>Cézanne</td>
<td>France</td>
</tr>
</table>
The class attribute assigns one or more classnames to the <col> tag.
Multiple classnames are separated by a space.
Classes (i.e. classnames) are used for styling the col element.
JavaScript uses classes to access elements by classname.
Tip: class is a global attribute that can be applied to any HTML element.
<col class="classnames" />
| Value | Description |
|---|---|
| classnames | One or more space-separated class names. |
A class attribute styling a <col> element.
Clicking the button toggles a classname that changes the background color.
| Id | First Name | Last Name | Country |
|---|---|---|---|
| ART-303 | Vincent | Van Gogh | Netherlands |
| ART-877 | Paul | Cézanne | France |
<style>
table.tbl { width:100%; border-collapse: collapse; }
.tbl th, .tbl td { padding:3px; border: 1px solid #777; }
.col-mint { background: mintcream; }
.col-blue { background: lightblue; }
</style>
<table class="tbl">
<colgroup>
<col id="mycol" class="col-mint">
<col span="3">
</colgroup>
<tr>
<th>Id</th>
<th>First Name</th>
<th>Last Name</th>
<th>Country</th>
</tr>
<tr>
<td>ART-303</td>
<td>Vincent</td>
<td>Van Gogh</td>
<td>Netherlands</td>
</tr>
<tr>
<td>ART-877</td>
<td>Paul</td>
<td>Cézanne</td>
<td>France</td>
</tr>
</table>
<br/>
<button onclick="toggle();">Toggle class</button>
<script>
let toggle = () => {
let col = document.getElementById("mycol");
col.classList.toggle("col-blue");
}
</script>
Two CSS classes are defined in the <style> element.
The class attribute in <col> assigns one classname.
Repeatedly clicking the button toggles the second class, changing the background color of the element.
Here is when class support started for each browser:
 Chrome
|
1.0 | Sep 2008 |
 Firefox
|
1.0 | Sep 2002 |
 IE/Edge
|
1.0 | Aug 1995 |
 Opera
|
1.0 | Jan 2006 |
 Safari
|
1.0 | Jan 2003 |
Back to <col>
