| <!DOCTYPE html> |
| <title>Layout Instability: off-screen content-visibility:auto content</title> |
| <link rel="help" href="https://wicg.github.io/layout-instability/" /> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="resources/util.js"></script> |
| <script> |
| // These scripts need to be before the contents because we need to ensure no |
| // layout shifts during page load. |
| promise_test(async () => { |
| const watcher = new ScoreWatcher; |
| |
| // Wait for the initial render to complete. |
| await waitForAnimationFrames(2); |
| |
| window.scrollTo(0, 100000 + 100); |
| await waitForAnimationFrames(2); |
| |
| assert_equals(watcher.score, 0); |
| |
| // This should report a layout shift as target is now visible. |
| target.style.top = '100100px'; |
| |
| await watcher.promise; |
| const expectedScore = computeExpectedScore(100 * 100, 100); |
| assert_equals(watcher.score, expectedScore); |
| |
| // No new layout shift should be reported when target is scrolled out of screeen. |
| window.scrollTo(0, 0); |
| await waitForAnimationFrames(2); |
| |
| assert_equals(watcher.score, expectedScore); |
| }, 'off-screen content-visibility:auto'); |
| </script> |
| <style> |
| .auto { |
| content-visibility: auto; |
| contain-intrinsic-size: 1px; |
| width: 100px; |
| } |
| </style> |
| <div class=auto> |
| <div style="width: 100px; height: 100px; background: blue"></div> |
| </div> |
| <div id="target" class=auto style="position: relative; top: 100000px"> |
| <div style="width: 100px; height: 100px; background: blue"></div> |
| </div> |