HTML <strong> class Attribute

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

Homework is due on March 11.

  .strong { color: teal; }

  Homework is due on <strong class="strong">March 11</strong>.

Using class

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


<strong class="classnames">



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

More Examples

A class attribute styling a <strong> element.
Clicking the button toggles a classname that changes the text color.

Homework is due on March 11.

  .strong { color: teal; }
  .strong-tomato { color: tomato; }

  Homework is due on 
  <strong id="mystrong" class="strong">March 11</strong>.

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

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

Code explanation

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

The class attribute in <strong> assigns one classname.

Repeatedly clicking the button toggles another class, changing the strong text color.

Browser support

Here is when class support started for each browser:

1.0 Sep 2008
1.0 Sep 2002
1.0 Aug 1995
1.0 Jan 2006
1.0 Jan 2003

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Last updated on Sep 30, 2023