How Can I Efficiently Retrieve CSS Styles Using JavaScript?

Retrieving CSS Styles with JavaScript

Manipulating styles via JavaScript is a common task in web development. While setting styles is straightforward using the style property, obtaining the current value of a particular style can be more challenging.

In the past, accessing a specific style value required parsing the entire style string, a cumbersome process. However, modern browsers offer a convenient solution: getComputedStyle().

Using getComputedStyle()

The getComputedStyle() method returns an object representing the computed styles of an element. To retrieve the value of a specific style, simply use the getPropertyValue() method on the computed style object.

var element = document.getElementById('image_1');
var style = window.getComputedStyle(element);
var top = style.getPropertyValue('top');

This code retrieves the computed value of the top style property for the element with the ID image_1. The result is stored in the top variable. The window.getComputedStyle() method ensures the computed style is returned, accounting for any applied CSS rules and inline styles.

Example Usage

Consider the following HTML code:

<img>

Using getComputedStyle() to retrieve the current top position of the image:

var image = document.getElementById('image_1');
var topPosition = window.getComputedStyle(image).getPropertyValue('top');

The topPosition variable now contains the computed top position of the image, regardless of any applied CSS or inline styles.

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