How to Dynamically Change CSS Custom Properties with jQuery

Learn how to change the value of CSS custom properties by 1 upon button clicks using jQuery, with easy-to-follow code examples and explanations.
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How to Dynamically Change CSS Custom Properties with jQuery

In modern web development, it's common to want to change the styling of elements on the fly. One powerful way to manipulate styles is through CSS custom properties (often known as CSS variables). In this post, we will explore how to efficiently change the value of a CSS custom property by one each time a button is clicked, specifically in a jQuery-enabled scenario. This guide will break down the process, ensuring it’s easy to follow, even for beginners.

The Problem

You may find yourself in a situation where you need to increment the value of a CSS custom property based on user interaction, such as clicking a button. In the provided example, the goal is to increase the --slider-index variable each time the "Next" button is clicked, moving through a set of images or elements.

Initially, the attempt looked something like this:

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

Issues Identified

Re-declaration of x: The variable x is declared inside the click function. This means it resets to 0 every time the button is clicked.

Incorrect Incrementing: Using x+ + after setting the property means that the variable's value is set to 0 before incrementing, which is not the desired effect.

The Solution

To resolve these issues, we need to implement the following changes:

1. Declaring x Outside the Function

By defining x outside of the click handler, we allow it to retain its value between clicks:

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

2. Correcting the Increment

We change from using x+ + to + + x to ensure that x is incremented before being assigned to the --slider-index property.

Final Code Implementation

Putting it all together, here’s the complete code that achieves the desired effect:

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

Conclusion

Changing the value of CSS custom properties dynamically allows for interactive and responsive designs. By declaring your variable outside of the click event and utilizing pre-incrementing, you can ensure that your styles change properly with each button click. This basic structure can be the foundation for more complex interactions as you develop your skills in jQuery and JavaScript.

With this guide, you should now be able to successfully implement dynamic CSS variable changes using jQuery! Embrace these techniques to enhance your web projects and provide a more engaging user experience.