Implicit tracks will be excluded from the resolved values of the grid-template-rows and grid-template-columns. Previously, all tracks were included, whether implicit or explicit.
This change aims to make the resolved values round-trip, which is one of the most fundamental rules for getComputedStyle(). That is, reassigning the resolved value provided by getComputedStyle() as a specified value shouldn't change the number of tracks nor their sizes. The current behavior is problematic because the specified values of grid-template-rows and grid-template-columns are only able to define explicit tracks, while the resolved values include implicit tracks.
Specification currently under development in a Working Group
Status in Chromium
Consensus & Standardization
Last updated on 2021-08-22