Source code
Revision control
Copy as Markdown
Other Tools
<!DOCTYPE HTML>
<html>
<head>
  <title>APZ overscroll handoff for fixed elements</title>
  <script type="application/javascript" src="apz_test_utils.js"></script>
  <script type="application/javascript" src="apz_test_native_event_utils.js"></script>
  <script src="/tests/SimpleTest/paint_listener.js"></script>
  <meta name="viewport" content="width=device-width"/>
  <style>
html, body {
  height: 100%;
  overflow: hidden;
}
#main {
  height: 100%;
  overflow: auto;
}
#spacer  {
  height: 5000px;
}
#fixed {
  position: fixed;
  top: 50%;
  left: 0;
  width: 100%;
  height: 100px;
  background: red;
  overflow: auto;
}
#long {
  height: 250px;
  width: 50%;
  position: absolute;
  background: green;
  top: 0;
  left: 25%;
}
  </style>
</head>
<body>
  <div id="main">
    <div id="spacer">
    </div>
    <div id="fixed">
      <div id="long">
      </div>
    </div>
  </div>
</body>
<script type="application/javascript">
async function test() {
  // Scroll to the bottom of the fixed position element that should not
  // allow overscroll handoff.
  fixed.scrollTop = fixed.scrollHeight;
  // After scrolling to bottom tick the refresh driver.
  await promiseFrame();
  info("Start: fixed=" + fixed.scrollTop + " main=" + main.scrollTop);
  // Async scroll the fixed element by 200 pixels using the mouse-wheel.
  // This should not handoff the overscroll.
  await promiseMoveMouseAndScrollWheelOver(fixed, 50, 50, false, 200);
  // Make sure scrolling that has happened is propagated to the main thread.
  await promiseApzFlushedRepaints();
  // Try another gesture to ensure the overscroll handoff runs.
  await promiseMoveMouseAndScrollWheelOver(fixed, 50, 50, false, 200);
  await promiseApzFlushedRepaints();
  info("After scroll: fixed=" + fixed.scrollTop + " main=" + main.scrollTop);
  // Ensure that the main element has not scrolled.
  is(main.scrollTop, 0, "The overscroll should not handoff");
}
waitUntilApzStable()
.then(test)
.then(subtestDone, subtestFailed);
</script>
</html>