How can I get all the CSS rules applied to an element using pure JavaScript?

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<p>Finding Element-Specific CSS Rules in JavaScript

<p>In web development, understanding the CSS rules applied to an element is crucial for fine-tuning its appearance and behavior. Relying on developer tools like Firebug or the WebKit Inspector can provide insights into the compiled CSS rules influencing an element's rendering. However, replicating this functionality in pure JavaScript without additional plugins poses a challenge.

<p>To address this challenge, let's delve into a JavaScript function that achieves this task. The function, aptly named css, takes an HTML element as its input and returns an array of CSS rules that apply to it.

<p>The css function leverages the matches method, which supports cross-browser compatibility. It iterates over the stylesheets in the document, examining each CSS rule within those stylesheets. If an element's selector matches a rule's selectorText, the CSS text of that rule is added to an array.

<p>For instance, consider the following CSS and HTML:

p { color: red; }
#description { font-size: 20px; }

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<p>Calling css(document.getElementById('description')) would return an array containing the following two CSS rules:

p { color :red; }
#description { font-size: 20px; }

<p>By analyzing this array, developers can determine the source of specific CSS properties affecting an element and make adjustments accordingly. The css function, available on JSFiddle (http://jsfiddle.net/HP326/6/), offers a comprehensive solution for identifying CSS rules that shape an element's appearance in pure JavaScript, empowering developers to harness browser rendering capabilities in their own applications.

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