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CSS Properties and Values API

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The CSS Properties and Values API — part of the CSS Houdini umbrella of APIs — allows developers to explicitly define their CSS custom properties, allowing for property type checking, default values, and properties that do or do not inherit their value.

Interfaces

Examples

The following will register a custom property named --my-color using CSS.registerProperty in JavaScript. --my-color will use the CSS color syntax, it will have a default value of #c0ffee, and it will not inherit its value:

window.CSS.registerProperty({
  name: "--my-color",
  syntax: "<color>",
  inherits: false,
  initialValue: "#c0ffee",
});

The same registration can take place in CSS using the @property at-rule:

@property --my-color {
  syntax: "<color>";
  inherits: false;
  initial-value: #c0ffee;
}

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also