HTML <header> class Attribute

The class attribute assigns one or more classnames to the <header> 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 <header> element.

Company logo here...
  .header-dark {background:#1f2936; color:white; padding:10px;}

<header class="header-dark">
    Company logo here...

Using class

Classes (i.e. classnames) are used for styling the header 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.


<header class="classnames">



Value Description
classnames One or more space-separated class names.

More Examples

A class attribute styling a <header> element.
Clicking the button toggles a classname that changes the background and text colors.

Company logo here...

  .header-dark {background:#1f2936; color:white; padding:10px;}
  .header-indigo {background-color:#c6d2fe; color:black;}

<header id="myheader" class="header-dark">
    Company logo here...

<button onclick="toggle();">Toggle class</button>

  let toggle = () => {
    let element = document.getElementById("myheader");

Code explanation

Two CSS classes are defined in the <style> element.

The class attribute in <header> assigns one classname.

Repeatedly clicking the button toggles another class, changing the background and text color of the <header>.

Browser support

Here is when class support started for each browser:

6.0 Sep 2010
4.0 Mar 2011
9.0 Mar 2011
11.1 Mar 2011
5.0 Jun 2010

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Last updated on Sep 30, 2023