lang="..." vs lang=""
This test failed because it relies on :lang for results, but :lang is not supported by this browser.
If an element contains a lang attribute with an empty value, the value of a lang attribute higher up the document tree will no longer be applied to the content of that element.
This test uses :lang to detect whether the language has been set. If :lang is not supported, a message will appear and the test will fail.
Spec text: «Setting the attribute to the empty string indicates that the primary language is unknown.»