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Unlocking the Power of JavaScript - Changing Element Classes Made Easy

Anchal Rastogi
~ 7 min read | Published on Apr 12, 2024


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In the realm of web development, the ability to dynamically change an element's class using JavaScript is a fundamental skill that every developer should master. Whether it's applying different styles to elements based on user interactions, implementing animations, or toggling between different visual states, knowing how to manipulate classes with JavaScript opens up a world of possibilities. In this comprehensive guide, we'll explore various techniques and best practices for changing element classes with JavaScript, catering to developers of all skill levels.

Understanding the Importance of Changing Element Classes

Before we dive into the technical details, let's first understand why changing element classes dynamically is essential in web development:

  • Dynamic Styling: By changing an element's class, developers can apply different styles to elements based on various conditions or user interactions, enhancing the overall user experience.
  • State Management: Classes can be used to represent different states of an element, allowing developers to toggle between these states seamlessly.
  • Code Organization: Using classes to manage element styles promotes cleaner and more maintainable code, making it easier to understand and modify.

Now that we've established the importance of changing element classes, let's explore how developers can achieve this using JavaScript.

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Method 1: Using classList

The classList property provides a convenient way to manipulate classes on an element. It exposes methods like add, remove, toggle, and contains, which can be used to modify classes dynamically.

// Add a class to an element

// Remove a class from an element

// Toggle a class on an element

// Check if an element has a specific class
const hasClass = document.getElementById('myElement').classList.contains('className');


  • Provides a clean and intuitive API for class manipulation.
  • Allows developers to add, remove, toggle, and check for classes easily.


  • Limited browser support for older versions of Internet Explorer.

Method 2: Direct Manipulation of className

Alternatively, developers can manipulate an element's className property directly to change its classes. This method is straightforward but lacks some of the conveniences provided by classList.

// Add a class to an element
document.getElementById('myElement').className += ' newClass';

// Remove a class from an element
document.getElementById('myElement').className = document.getElementById('myElement').className.replace('oldClass', '');

// Check if an element has a specific class
const hasClass = document.getElementById('myElement').className.includes('className');


  • Simple and straightforward syntax.
  • Widely supported across all browsers.


  • Less intuitive and lacks the convenience of methods like add, remove, and toggle.
  • Can be prone to errors, especially when dealing with multiple classes.

Method 3: Using setAttribute

Although less commonly used, developers can also change an element's class by directly setting its class attribute using the setAttribute method.

// Set the class attribute of an element
document.getElementById('myElement').setAttribute('class', 'newClass');


  • Provides a programmatic way to set the class attribute.
  • Offers flexibility for specific use cases.


  • Less commonly used and may not be as intuitive for some developers.
  • Can overwrite existing class attributes entirely.

Choosing the Right Method

When deciding which method to use for changing element classes with JavaScript, developers should consider factors such as browser compatibility, ease of use, and specific project requirements. While classList offers a clean and intuitive API, direct manipulation of className may be preferable for simpler use cases or broader browser support.

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In conclusion, the ability to dynamically change an element's class using JavaScript is a valuable skill for web developers. Whether it's for dynamic styling, state management, or code organization, knowing how to manipulate classes opens up a myriad of possibilities for creating engaging and interactive web experiences.

Read more resources Javascript concepts

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