setting-scrollTop-after-hide-show.html

<!DOCTYPE html>
<html>
<script>
    if (window.testRunner)
        testRunner.dumpAsText();
    
    function log(message)
     {
         document.getElementById("console").appendChild(document.createTextNode(message + "\n"));
     }
</script>
<body>
    <p>In this test, we set a new scrollTop for a scrolling div, and then we make the div display:none. The test ensures that when we bring the div back by giving it a display value of block, that we also restore its scroll position. The test also ensures that we are able to set a new scrollTop value of 0 after that.</p>
    <div id="scroller" style="height: 20px; overflow: scroll;">
        <div style="height: 60px;"></div>
    </div>
    <pre id="console"></pre>
    <script>
    a = document.getElementById('scroller');
    a.scrollTop = 20;
    a.style.display = 'none';
    a.scrollTop = 20;
    a.style.display = 'block';
    log('scrollTop after restoring div: ' + a.scrollTop + '\n');
    a.scrollTop = 0;
    log('scrollTop after setting scrollTop back to 0: ' + a.scrollTop + '\n');
    </script>
</body>
</html>

chromium/third_party/blink/web_tests/fast/overflow/setting-scrollTop-after-hide-show.html