The class attribute assigns one or more classnames to the <th> tag.
Classnames are defined in a stylesheet or in a local <style> element.
Classes, i.e. classnames, are used to style elements.
A class attribute styling a <th> element.
| Customers | |
|---|---|
| Denice | Hobermann |
| Paulo | Cornell |
<style>
table.tb { width: 250px; border-collapse: collapse; }
.tb th, .tb td { border: solid 1px #777; padding: 5px; }
.th-blue { background-color:lightblue; }
</style>
<table class="tb">
<tr>
<th class="th-blue" colspan="2">Customers</th>
</tr>
<tr>
<td>Denice</td>
<td>Hobermann</td>
</tr>
<tr>
<td>Paulo</td>
<td>Cornell</td>
</tr>
</table>
Classes (i.e. classnames) are used for styling the th element.
Multiple classnames are separated by a space.
JavaScript uses classes to access elements by classname.
Tip: class is a global attribute that can be applied to any HTML element.
<th class="classnames">
| Value | Description |
|---|---|
| classnames | One or more space-separated class names. |
A class attribute styling a <th> element.
Clicking the button toggles a classname that changes the header cell to dark mode.
| Customers | |
|---|---|
| Denice | Hobermann |
| Paulo | Cornell |
<style>
table.tb { width: 250px; border-collapse: collapse; }
.tb th, .tb td { border: solid 1px #777; padding: 5px; }
.th-blue { background-color:lightblue; }
.th-dark { background-color: #222; color: #fff; }
</style>
<table class="tb">
<tr>
<th id="myth" class="th-blue" colspan="2">Customers</th>
</tr>
<tr>
<td>Denice</td>
<td>Hobermann</td>
</tr>
<tr>
<td>Paulo</td>
<td>Cornell</td>
</tr>
</table>
<br />
<button onclick="toggle();">Toggle class</button>
<script>
let toggle = () => {
let element = document.getElementById("myth");
element.classList.toggle("th-dark");
}
</script>
Two CSS classes are defined in the <style> element.
The class attribute in <th> assigns one classname.
Repeatedly clicking the button toggles another class, changing the <th> background and text color of the table header cell.
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 <th>
