This page tests selector query and style invalidation performance with :has().
To check the complexity of selector query, this test shows how the processing
time increases as the tree size increases.
To determine the absolute level of style invalidation performance with :has(), this test compares the performance of style invalidation with and without :has(). Also, this test shows how the style invalidation processing time increases as the number of style rules increases.
For each step of checking processing time, the operations will be called multiple times to get average performance of each operation. Due to this, this test will take some time.