Скачать или смотреть How to Select a JavaScript Element by z-index and Change its Background Color

Learn how to effectively select an element in JavaScript based on its `z-index` and change its background color using jQuery. In this guide, we will walk you through the steps in a clear and easy manner!
---
This video is based on the question https://stackoverflow.com/q/75141441/ asked by the user 'Developer' ( https://stackoverflow.com/u/20821229/ ) and on the answer https://stackoverflow.com/a/75141528/ provided by the user 'yuta y' ( https://stackoverflow.com/u/19524218/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Selecting an element with JavaScript (z-index)

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Select a JavaScript Element by z-index and Change its Background Color

In web development, you might find yourself needing to manipulate elements on a page based on their CSS properties. One common task could be changing the appearance of certain elements defined by their z-index values. In this guide, we will address a question frequently posed by developers: How can I select an element whose z-index is equal to 3 and change its background color to red?

Understanding the Problem

When you are dealing with stacked elements in HTML using CSS, the z-index property allows you to control the vertical stacking order of elements. A higher z-index means the element will appear on top of others. This task is especially relevant when dealing with layered designs that require distinct visual indicators.

The Code Structure

Here is a simplified representation of the HTML structure you'll be working with:

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

Your goal is to select the <li> elements with a specific z-index and change their background color to red.

The Solution

To achieve this, we'll use jQuery, a popular JavaScript library, which simplifies DOM manipulation. Below are the steps you need to follow to select the element by z-index and update its background color.

Step-by-Step Breakdown

Iterate through each <li> Element: Use the each() function to go through all <li> elements in your unordered list.

Check the z-index Value: For each <li> element, check if its z-index is equal to 3.

Change the Background Color: If the z-index is indeed 3, change the background color of that specific element to red.

Implementation in Code

Here’s the correct jQuery script that accomplishes the task:

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

Explanation of the Code

$("li").each(function(index) {...}: This line selects all list items and begins a loop over each item using jQuery.

if ($(this).css("z-index") == 3): Here, we are checking the computed CSS value of z-index for each list item.

$(this).css("background-color", "red"): If the condition meets (i.e., z-index is 3), this line changes the item's background color to red.

Conclusion

By following these steps, you can easily select specific elements based on their z-index and modify their appearance with jQuery. This is a powerful skill for any web developer, as it allows for dynamic changes and effective presentations of layered content. If you encounter any issues during implementation, double-check the element styles and ensure jQuery is properly linked in your project.

Feel free to try out this code in your projects and enhance your web pages dynamically!