CSSFontFaceDescriptors

The CSSFontFaceDescriptors interface represents a CSS declaration block for an @font-face at-rule.

Each descriptor in the body of the corresponding @font-face at-rule can be accessed using either its kebab-case property name in bracket notation or the camel-case version of the property name in dot notation. For example, you can access the font-family CSS descriptor as style["font-family"] or style.fontFamily, where style is a CSSFontFaceDescriptors instance.

Note: The CSSFontFaceRule interface represents a @font-face at-rule, and the CSSFontFaceRule.style property is an instance of this object.

Instance properties

Inherits properties from its ancestor CSSStyleDeclaration.

The following property names, in kebab-case (accessed using bracket notation) and camel-case (accessed using dot notation), each represent the value of a descriptor in the corresponding @font-face at-rule:

font-display or fontDisplay: A string representing the value of the font-display descriptor.
font-family or fontFamily: A string representing the value of the font-family descriptor.
font-feature-settings or fontFeatureSettings: A string representing the value of the font-feature-settings descriptor.
font-stretch or fontStretch: A string representing the value of the font-stretch descriptor.
font-style or fontStyle: A string representing the value of the font-style descriptor.
font-weight or fontWeight: A string representing the value of the font-weight descriptor.
font-width or fontWidth: A string representing the value of the font-width descriptor.
size-adjust or sizeAdjust: A string representing the value of the size-adjust descriptor.
src: A string representing the value of the src descriptor.
unicode-range or unicodeRange: A string representing the value of the unicode-range descriptor.

Instance methods

No specific methods; inherits methods from its ancestor CSSStyleDeclaration.

Examples

undefined

Accessing @font-face descriptor values

This example defines a @font-face rule and then uses CSSFontFaceDescriptors to read back the descriptor values.

CSS

css

@font-face {
  font-family: "MyHelvetica";
  src:
    local("Helvetica Neue Bold"),
    local("HelveticaNeue-Bold"),
    url("MgOpenModernaBold.woff2") format("woff2");
  font-weight: bold;
  font-style: normal;
  font-display: swap;
}

#log {
  height: 200px;
  overflow: scroll;
  padding: 0.5rem;
  border: 1px solid black;
}

<pre id="log"></pre>

const logElement = document.querySelector("#log");
function log(text) {
  logElement.innerText = `${logElement.innerText}${text}\n`;
  logElement.scrollTop = logElement.scrollHeight;
}

JavaScript

const myRules = document.getElementById("css-output").sheet.cssRules;
for (const rule of myRules) {
  if (rule instanceof CSSFontFaceRule) {
    const style = rule.style; // a CSSFontFaceDescriptors
    log(`font-family: ${style.fontFamily}`);
    log(`src: ${style.src}`);
    log(`font-weight: ${style["font-weight"]}`);
    log(`font-style: ${style.fontStyle}`);
    log(`font-display: ${style["font-display"]}`);
  }
}

Result

Specifications

CSS Fonts Module Level 4