The class attribute assigns one or more classnames to the <h1> to <h6> tags.
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 an <h3> element.
<style>
.heading-3 {display:inline-block;
border-bottom:3px solid #808cf8; padding-bottom:5px;}
</style>
<article>
<h3 class="heading-3">The Innocence Project</h3>
</article>
Classes (i.e. classnames) are used for styling the h1-h6 elements.
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.
<h1 class="classnames">
| Value | Description |
|---|---|
| classnames | One or more space-separated class names. |
A class attribute styling an <h3> element.
Clicking the button toggles a classname that changes the bottom border color.
<style>
.heading-3 {display:inline-block;
border-bottom:3px solid #808cf8; padding-bottom:5px;}
.border-red { border-bottom-color: orangered; }
</style>
<section>
<h3 id="myheading" class="heading-3">The Paris-Dakar rally</h3>
</section>
<br/>
<button onclick="toggle();">Toggle class</button>
<script>
let toggle = () => {
let element = document.getElementById("myheading");
element.classList.toggle("border-red");
}
</script>
Two CSS classes are defined in the <style> element.
The class attribute in <h3> assigns a single classname.
Repeatedly clicking the button toggles another class, changing the border 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 <h1 to h6>
