v134 · css / cssom

Font Feature Catalog

Walk the CSSOM to find every @font-feature-values rule on the page, read its aliases via the newly-exposed CSSFontFeaturesValueRule interface, and display a structured catalog. Toggle aliases to see live font rendering changes.

checking CSSFontFeaturesValueRule…
Before Chrome 134, window.CSSFontFeaturesValueRule was undefined — the interface wasn't exposed even though the rules existed. Now tooling can walk document.styleSheets, find rule instanceof CSSFontFeaturesValueRule, and read rule.fontFamily, rule.valueText directly — no regex on cssText needed.

Font feature catalog (CSSOM walk)

CSSFontFeaturesValueRule properties

Rule indexfontFamilytype (block)valueText (aliases)CSSFontFeaturesValueRule?

Live rendering — toggle aliases

Sample text with font-variant-alternates

Typography Showcases — Swash & Ligatures
No features active

What the rule object exposes

Click "Walk CSSOM" to read rules.