Thanks for point out, it is do shipped in FF.
A question about the return value of getComputedStyle:
, it says:
"The values returned by getComputedStyle are known as resolved values
. These are usually the same as the CSS 2.1 computed values, but for some older properties like width, height or padding, they are instead the used values.
"but CSS 2.1 redefined computed values as pre-layout, and used values as post-layout. "
And here, https://drafts.csswg.org/cssom/#resolved-values
"getComputedStyle() was historically defined to return the "computed value"
of an element or pseudo-element."
And in CSSComputedStyleDeclaration::getPropertyCSSValue, before return value, it will call document().updateStyleAndLayoutTreeForNode.
So for chromium, does it always return the computed value(document().updateStyleAndLayoutTreeForNode didn't trigger layout.)?