css/cssom/getComputedStyle-display-none-002.html

<!doctype html>
<meta charset="utf-8">
<title>CSSOM: getComputedStyle gets invalidated for display: none elements (rules)</title>
<link rel="help" href="https://drafts.csswg.org/cssom/#dom-window-getcomputedstyle">
<link rel="help" href="https://bugs.webkit.org/show_bug.cgi?id=186882">
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<style>
#undisplayed {
  display: none;
  color: red;
}
.sibling + #undisplayed {
  color: green;
}

.sibling + #undisplayed > div {
  color: yellow;
}
</style>
<div id="helper"></div>
<div id="undisplayed"><div id="child"></div></div>
<script>
  test(function() {
    let undisplayed_style = getComputedStyle(undisplayed);
    let undisplayed_child_style = getComputedStyle(child);
    assert_equals(undisplayed_style.color, "rgb(255, 0, 0)");
    assert_equals(undisplayed_child_style.color, "rgb(255, 0, 0)");
    helper.classList.add("sibling");
    assert_equals(undisplayed_style.color, "rgb(0, 128, 0)");
    assert_equals(undisplayed_child_style.color, "rgb(255, 255, 0)");
  }, "getComputedStyle gets invalidated in display: none subtrees due to rule matching changes");
</script>