How to Fix the Uncaught TypeError in JavaScript: Toggle Class on Click

Learn how to resolve the `Uncaught TypeError` and properly use JavaScript to toggle a class with a click event.
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How to Fix the Uncaught TypeError in JavaScript: Toggle Class on Click

The Problem

You want to create a simple interaction where clicking a circle changes its color: turning red when active and reverting to its original color when clicked again. You might have written code that seems correct on the surface but still fails to work, leading to that dreaded TypeError in the console.

The Error Explained

The Solution

Step 1: Use querySelector

Change your selection method from querySelectorAll() to querySelector(). querySelector() fetches the first matching element, making it suitable for this task since you're working with a single element.

Revised Code

Here’s how the corrected JavaScript looks:

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

CSS for Visual Effect

Ensure you have the following CSS in place to style the element:

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

HTML Structure

Here’s a simple HTML structure you need to include:

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

Conclusion

By following these steps, you can successfully eliminate the TypeError and create the interactive experience you desire. Remember to always ensure you're selecting the correct type of elements in your JavaScript code. With these adjustments, clicking on the circle should now correctly toggle its active state, creating a smoother user experience!

With this solution, you're not just fixing the problem—you're enhancing your coding skills. Happy coding!