Hi, This week I landed bug 1363805[1], which will skip restyling if the element does not need that for getting correct value. Normal users should not notice any difference, but this change may affect some test cases which need to force restyle.
The optimization only happens when the element satisfies *all* the following conditions: 1. The CSS property does not depend on layout. 2. getComputedStyle and the element belong to the same document. 3. The document does not need to restyle for this element, i.e. 3-1. The document has a presshell. 3-2. The style set has not changed yet. 3-3. All ancestors (including the element itself) are not animating. 3-4. All ancestors (including the element itself) do not need to restyle themselves. 4. All ancestor documents satisfy 3 for the sub-document. For example, getComputedStyle(document.body).color will not trigger restyling if only descendants have changed but not document.body itself. If you are not sure (or just don't care about it), choose a layout dependent property will do the trick. (e.g.: getComputedStyle(document.body).width) [1]: https://bugzilla.mozilla.org/show_bug.cgi?id=1363805 Cheers, Wei-Cheng Pan _______________________________________________ dev-platform mailing list [email protected] https://lists.mozilla.org/listinfo/dev-platform
