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Learn how to dynamically change the class name of an HTML element using JavaScript with easy-to-follow steps and examples.
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How to Dynamically Change an HTML class Name Using JavaScript

Have you ever needed to modify the styles of an HTML element on the fly? Maybe you have a web page action that should trigger a change in styling, such as clicking a button or loading new content. In this guide, we’ll learn how to change the class name of an HTML element using JavaScript.

The Problem

Imagine you have an HTML element like a <div> with an ID and class name assigned to it:

[[See Video to Reveal this Text or Code Snippet]]

If you want to change this class name dynamically using JavaScript, you might wonder how to do it correctly. A common misconception is to use a method like changeClassName, but this isn't a valid JavaScript method. Instead, let's explore the proper way to change the class name.

The Solution

To change the class name of an HTML element in JavaScript, you can use the classList property, which provides methods for adding, removing, and toggling classes. Here’s a step-by-step approach:

Step 1: Select the HTML Element

First, you need to select the HTML element whose class name you want to change. In our example, we have a <div> with the ID ThisIsId. You can easily select it using:

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Remove the Old Class

Once you have selected the element, the next step is to remove the old class name. To do this, use the classList.remove() method like so:

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Add the New Class

Now that the old class has been removed, you can add a new class using the classList.add() method:

[[See Video to Reveal this Text or Code Snippet]]

Complete Example

Putting it all together, here’s what your final script should look like:

[[See Video to Reveal this Text or Code Snippet]]

Notes on Class Management

Multiple Classes: If an element has multiple classes, you can remove or add them in the same manner. For example, if you want to change from class="foo bar" to class="baz", first remove foo and bar, then add baz.

Class Toggle: You can also use classList.toggle() to toggle a class on and off.

Conclusion

Changing an HTML element's class name dynamically with JavaScript is an essential skill for creating interactive web pages. By using the classList methods, you can easily modify styles and enhance user experiences. So next time you need to change a class name, remember these simple steps and methods! Happy coding!