Скачать или смотреть How to Create a Dynamic Background Color Change with JavaScript on Window Resize

Learn how to effectively change the body background color using JavaScript based on screen size changes without needing to refresh the browser.
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This video is based on the question https://stackoverflow.com/q/69595940/ asked by the user 'Ren Jitsm' ( https://stackoverflow.com/u/12993662/ ) and on the answer https://stackoverflow.com/a/69595953/ provided by the user 'Rateb Habbab' ( https://stackoverflow.com/u/9765910/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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Creating a Dynamic Background Color Change with JavaScript

Have you ever wanted to create an interactive web experience by changing the background color of your webpage dynamically? This type of feature can greatly enhance your website's user experience. In this guide, we'll walk through how to use vanilla JavaScript to change the background color of a web page when the window is resized. Specifically, we will change the background to red if the screen width is less than 500 pixels and to green when it’s equal to or greater than 500 pixels.

Understanding the Problem

When resizing the browser window, it's common to want some visual feedback that indicates how the design responds to different screen sizes. You might have a function that works well when the page loads but doesn't update dynamically during a resize event. This can lead to confusion and a less interactive experience for users. The goal is to execute a JavaScript function every time the window is resized, making the necessary adjustments without needing to refresh the page.

Original Approach

You may start with a function similar to the following:

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

In this setup, the doit function checks the screen width and changes the body background color accordingly. However, it only executes once when the page loads, not upon resizing. This is where improvement is needed.

The Solution: Adding Event Listeners

To ensure our function runs every time the window is resized, we can attach an event listener to the window object. Let's break down your improved function step by step.

Step-by-Step Breakdown

Define your function: This function will handle both the initial color setting and the color changing based on window resizing.

Use window.addEventListener: This allows you to listen for the 'resize' event and execute your function each time the window is resized.

Here's how you can implement these steps:

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

Important Parts Explained

The fn Function: It checks the current width of the window and changes the body color accordingly. This nested function is essential because it allows us to execute the same logic for both the initial load and future resize events.

Event Listener: By using window.addEventListener('resize', fn), we ensure that the fn function runs every time the window size changes, providing a responsive experience without needing a page refresh.

Conclusion

By utilizing an event listener, we can create a web page that responds dynamically to changes in window size. This enhancement not only improves usability but also creates a more interactive visual presentation. Feel free to experiment with different colors and sizes to see how the interaction plays out. Happy coding!