<!DOCTYPE html> <title>Layout Instability: shift with counter scroll and translate not counted</title> <link rel="help" href="https://wicg.github.io/layout-instability/" /> <style> .scroller { overflow: scroll; position: absolute; left: 20px; top: 20px; width: 200px; height: 200px; } .content { width: 600px; height: 600px; } .changer { position: relative; background: yellow; left: 10px; top: 100px; width: 150px; height: 150px; } </style> <div id="scroller1" class="scroller"> <div class="content"> <div id="changer1" class="changer"></div> </div> </div> <div id="scroller2" class="scroller"> <div class="content"> <div id="changer2" class="changer"></div> </div> </div> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <script src="resources/util.js"></script> <script> promise_test(async () => { const watcher = new ScoreWatcher; // Wait for the initial render to complete. await waitForAnimationFrames(2); changer1.style.top = "250px"; changer1.style.translate = "0 -50px"; // 250 - 50 = 200; old position is 100; hence scrollTop to counter is 100. scroller1.scrollTop = 100; changer2.style.left = "220px"; changer2.style.translate = "80px 0"; // 220 + 80 = 300; old position is 10; hence scrollTop to counter is 290. scroller2.scrollLeft = 290; await waitForAnimationFrames(3); assert_equals(watcher.score, 0); }, "Shift with counter scroll and translate not counted."); </script>