v147 · css · interop fix

CSS update: decoupling of Width and Style properties

Chrome 147 aligns with Firefox and Safari: the computed values of border-width, outline-width, and column-rule-width are now independent of their corresponding *-style properties. Previously Chrome forced the computed width to 0px when style was none or hidden; now the author-specified width is always reflected in getComputedStyle().

what changed

Property	Before Chrome 147	Chrome 147+
`border-width`	Computed value forced to `0px` when `border-style: none`	Computed value reflects the authored value regardless of `border-style`
`outline-width`	Computed value forced to `0px` when `outline-style: none`	Computed value and resolved value both reflect the authored value
`column-rule-width`	Computed value forced to `0px` when `column-rule-style: none`	Computed value and resolved value both reflect the authored value

Source: chromestatus — CSS update: decoupling of Width and Style properties, May 2026.

why it matters

Pages that read getComputedStyle().borderWidth or outlineWidth — for example, to compute layout or animate from a base state — now get the authored value reliably across Chrome, Firefox, and Safari. Code that worked on Firefox and was wrong on Chrome no longer needs a workaround.

/* Chrome 147+ — these read back 4px even though there's no visible border */
.box {
  border-style: none;
  border-width: 4px;
}

const w = getComputedStyle(box).borderWidth;
// Chrome 147+: "4px"  (previously: "0px")
// Firefox: "4px"
// Safari: "4px"

Source: chromestatus and CSS Backgrounds Level 3, May 2026.

quick reference

Affected properties	`border-width` · `outline-width` · `column-rule-width`
Interop	Now matches Firefox and Safari behaviour
Shipped in	Chrome 147 (desktop + Android)
ChromeStatus	5133099851317248 — CSS update: decoupling of Width and Style properties
Spec	CSS Backgrounds and Borders Level 3

Source: chromestatus, May 2026.