CSSRuleList: length property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2015.

The length property of the CSSRuleList interface returns the number of CSSRule objects in the list.

An integer.

In the following example the number of items in the CSSRuleList named myRules is printed to the console.

let myRules = document.styleSheets[0].cssRules;
console.log(myRules.length);

Specification
CSS Object Model (CSSOM) # dom-cssrulelist-length

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