HTML <strong> class Attribute

The class attribute on a <strong> tag assigns one or more classnames to the strong importance element. Classes are used to style elements. Classnames are defined in a stylesheet or in a local <style> element.

Example

#

A class attribute styling a <strong> element.

Homework is due on March 11.

<style>
  .strong { color: teal; }
</style>

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

Using class

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

Multiple classnames are separated by a space.

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

JavaScript uses classes to access one or more elements by classname.

Tip:  class is a global attribute that can be applied to any HTML element.


Syntax

<strong class="classnames">

Values

#

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.


<style>
  .strong { color: teal; }
  .strong-tomato { color: tomato; }
</style>

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

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

<script>
  let toggle = () => {
     let element = document.getElementById("mystrong");
     element.classList.toggle("strong-tomato");
  }
</script>

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:

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

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