chromium/third_party/blink/web_tests/external/wpt/css/css-anchor-position/try-tactic-base.html

<!DOCTYPE html>
<title>CSS Anchor Positioning: try-tactic, base values</title>
<link rel="help" href="https://drafts.csswg.org/css-anchor-position-1/#typedef-position-try-fallbacks-try-tactic">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
  #cb {
    position: absolute;
    width: 400px;
    height: 200px;
    border: 1px solid black;
  }
  #target {
    position: absolute;
    /* Does not fit initially */
    width: 150px;
    height: 300px;
    border: 3px solid skyblue;
  }
</style>
<div id=cb>
  <div id=target></div>
</div>
<script>
  test(() => {
    let cs = getComputedStyle(target);
    assert_equals(cs.width, '150px');
    assert_equals(cs.height, '300px');

    target.style.positionTryFallbacks = 'flip-start';

    assert_equals(cs.width, '300px');
    assert_equals(cs.height, '150px');
  }, 'flip-start affects base values');
</script>