How to Select and Manipulate CSS pseudo-elements using JavaScript / jQuery ?

Last Updated : 02 Aug, 2023

In this article, we will learn how to select and manipulate CSS pseudo-elements using JavaScript (or jQuery). CSS pseudo-elements allow developers to style and enhance specific parts of an HTML document with the help of selectors like::before and::after, which provide the flexibility to add decorative content, modify layouts, and create unique visual effects. Here we are manipulating CSS pseudo-element with the help of Javascript or jQuery methods.

A CSS pseudo-element is a keyword added to a selector that lets you style a specific part of the selected elements. For Example, Styling the first letter or line of an element.

Approach 1: Using JavaScript

The first approach to select and manipulate the CSS pseudo-elements is by using JavaScript. In this, we are going to use the::after pseudo-element of CSS to manipulate its styles, etc.

Example: Below example demonstrates selecting and manipulating the:: after pseudo-element using Javascript.

In JavaScript, an event listener is added to the .myclass element. When the element is hovered over, the data-content attribute is updated with the value "This is Hovered After". When the mouse moves out of the element, the data-content attribute is set back to "This is After".

HTML

<!DOCTYPE html>
<html>

<head>
    <style>
        .myclass::after {
            content: attr(data-content);
            color: green;
            font-size: 30px
        }
    </style>
</head>

<body>
    <h1 style="color: green;">
        GeeksforGeeks
    </h1>

    <h2>
        How to select and manipulate CSS
        pseudo-elements in JavaScript
    </h2>
    
    <div class="myclass" data-content="This is After"></div>
    
    <script>
        document.addEventListener("DOMContentLoaded",
            function () {
                let myclass = document.querySelector('.myclass');

                myclass.addEventListener("mouseover",
                    function () {
                        myclass.setAttribute('data-content',
                            'This is Hovered After');
                    });

                myclass.addEventListener("mouseout",
                    function () {
                        myclass.setAttribute('data-content',
                            'This is After');
                    });
            });
    </script>
</body>

</html>

Output:

ezgifcom-crop-(33).gif

Approach 2: Using jQuery

The second approach to select and manipulate the CSS pseudo-elements is by using jQuery. Here, we will be using the attr() function that allows you to retrieve the value of an attribute and use it as a value for a CSS property.

Example: Below example demonstrates selecting and manipulating of: after pseudo-element using jQuery attr() and hover() method.

HTML

<!DOCTYPE html>
<html>

<head>
    <style>
        .myclass::after {
            content: attr(data-content);
            color: green;
        }
    </style>
  
    <script src=
"https://code.jquery.com/jquery-3.6.0.min.js">
    </script>
</head>

<body>
    <h1 style="color: green;">
        GeeksforGeeks
    </h1>
    <h2>How to select and manipulate CSS
        pseudo-elements jQuery
    </h2>
    <div class="myclass" 
         data-content="This is After">
      </div>
    <script>
        $(document).ready(function () {
            $('.myclass').hover(
                function () {
                    $(this).attr('data-content', 
                                 'This is Hovered After');
                },
                function () {
                    $(this).attr('data-content', '');
                }
            );
        });
    </script>
</body>

</html>