1console.log("hello-world);
javascript
console.log("hello-world);
hidden codeblock for CSS
css
.container {
  width: 80%;
}
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html
<pre><code class="language-css">
.container {
  width: 80%;
}
</code></pre>
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Code Carnage
1console.log("hello-world);
javascript
console.log("hello-world);
hidden codeblock for CSS
css
.container {
  width: 80%;
}
hidden codeblock for CSS
html
<pre><code class="language-css">
.container {
  width: 80%;
}
</code></pre>
hidden codeblock for CSS

Dynamic Class Manipulation On HTML Elements In JavaScript: Safeguarding Your Styles

ReadTime: 4 minutes

Greetings! 😀 In this blogpost , we will see how to dynamically manipulate classes on the `<body>` (or any other) HTML element using JavaScript. We’ll also see the safety and efficiency of classList methods, especially when dealing with multiple classes and potentially missing class names. Let’s dive in!

Selecting the Body Element

We’ll cover examples by modifiying classes on using <body> element, but you can apply same on any other HTML elements.

javascript
const bodyElement = document.body;
Selecting body element using javascript

Now that we have our target in sight, let’s see the methods for adding, removing, and toggling classes on it.

Method 1: Direct Class Assignment

First up, the direct class assignment. While it may seem straightforward, appending classes directly to className might be less elegant when dealing with multiple classes:

javascript
document.body.className += ' dark-mode';
Direct class assignment

Here, a space is crucial to separate the added class from existing ones. However, it lacks the precision and safety that classList methods offer.

Method 2: Classlist Methods

Add ClassList function

The classList.add() method proves to be more elegant and safer, especially when dealing with multiple classes:

javascript
document.body.classList.add('dark-mode', 'large-font');
classList.add to add multiple classes

This method accepts multiple classes as arguments, ensuring a clean and organized way to handle diverse styling scenarios.

Remove ClassList function

When it’s time to bid adieu to a class, classList.remove() provides a precise solution:

javascript
document.body.classList.remove('dark-mode');
classlist.remove to dynamically remove classes

This method ensures that the specified class is gracefully removed, avoiding unintentional removal of other classes that might share similar names.

Toggle Classlist Function

The classList.toggle() method offers flexibility, especially when dealing with dynamic user interactions:

javascript
document.body.classList.toggle('dark-mode');
toggle classlist

This method excels in scenarios where you want to toggle a class on and off, catering to features like light/dark mode switches.

The Safety Net of ClassList Methods

Now, let’s address the safety concerns when dealing with multiple classes and potential missing class names.

Handling Multiple Classes

Consider a scenario where you want to add multiple classes, but some might already exist. Using classList.add() ensures each class is added only if it’s not already present, preventing unintended duplication:

javascript
document.body.classList.add('dark-mode', 'large-font');
adding multiple classes without duplication

Handling Missing Class Names Gracefully

If you attempt to remove a class that doesn’t exist, classList.remove() gracefully handles it without throwing errors. This safety net minimizes the risk of runtime errors.

javascript
document.body.classList.remove('non-existent-class');
gracefully remove classes without runtime errors with classList.remove()

🧪Practice Coding Problem: Dynamic Class Toggling

In the spirit of Test Driven Development ( 😁), lets test our understanding by solving a problem.

Create a button that dynamically toggles the presence of the “highlight” class on the element. Write code for such a JavaScript function (referred toggleHighlight() in below HTML ) to achieve this dynamic behavior. You can place it in scripts.js file.

html
<!-- HTML -->
<!DOCTYPE html>
<html lang="en">
  <head>
      <meta charset="UTF-8" />
      <title>Dynamic Class Toggling</title>
      <style>
          .highlight {
              background-color: yellow;
          }
      </style>
  </head>
  <body>
      <button onclick="toggleHighlight()">Toggle Highlight</button>
      <script src="script.js"></script>
  </body>
</html>
Problem Code

Please attempt before seeing the Answer:

Solution
javascript
// JavaScript (script.js)
function toggleHighlight() {
  document.body.classList.toggle('highlight');
}
Solution Code

In conclusion, dynamically manipulating classes on the element is not only about style but also about safety and efficiency. The classList methods provide a robust toolkit for adding, removing, and toggling classes, ensuring your web applications stay stylish and error-free.

May your web pages are always updated with latest styles💻✨.

Keep coding, in style!

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