This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The read-only initialValue nullable property of the CSSPropertyRule interface returns the initial value of the custom property registration represented by the @property rule, controlling the property’s initial value.


const initialValue = CSSPropertyRule.initialValue;


A USVString which is a <declaration-value> as defined in CSS Syntax 3.


This stylesheet contains a single @property rule. The first CSSRule returned will be a CSSPropertyRule representing this rule. The initialValue property returns the string "#c0ffee" this being the value of the initial-value property in the CSS.

@property --property-name {
  syntax: '<color>';
  inherits: false;
  initial-value: #c0ffee;
let myRules = document.styleSheets[0].cssRules;
console.log(myRules[0].initialValue); //the string "#c0ffee"


Specification Status Comment
CSS Properties and Values API Level 1
The definition of 'InitialValue' in that specification.
Working Draft Initial definition.

Browser compatibility

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