| <!DOCTYPE html> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io"> |
| <link rel="author" title="Mozilla" href="https://mozilla.org"> |
| <link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1559627"> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-anchoring/#suppression-triggers"> |
| <style> |
| body, h1 { |
| margin: 0 |
| } |
| .sticky { |
| width: 100%; |
| top: 0; |
| left: 0; |
| } |
| .sticky > div { |
| width: 100%; |
| height: 50px; |
| background: darkblue; |
| } |
| header { |
| background: lightblue; |
| } |
| main { |
| background: lightgrey; |
| height: 200vh; |
| } |
| </style> |
| <header> |
| <h1>Some title</h1> |
| <span class="sticky"><div>Sticky header</div></span> |
| </header> |
| <main> |
| Some actual content. |
| </main> |
| <script> |
| const sticky = document.querySelector(".sticky"); |
| const nonStickyOffset = sticky.firstElementChild.offsetTop; |
| const t = async_test("Scroll offset adjustments are correctly suppressed when changing the position of an inline"); |
| let firstEvent = true; |
| window.onscroll = t.step_func(function() { |
| sticky.style.position = |
| document.documentElement.scrollTop > nonStickyOffset ? "fixed" : "static"; |
| if (firstEvent) { |
| firstEvent = false; |
| requestAnimationFrame(t.step_func(function() { |
| requestAnimationFrame(t.step_func_done(function() { |
| assert_equals(sticky.style.position, "fixed", "Element should become and remain fixed") |
| })); |
| })); |
| } |
| }); |
| window.onload = t.step_func(function() { |
| window.scrollTo(0, nonStickyOffset + 1); |
| }); |
| </script> |
