| <!DOCTYPE html> |
| <style> |
| .composited-box { |
| position: absolute; |
| left: 0; |
| top: 1000px; |
| height: 300px; |
| width: 300px; |
| will-change: transform; |
| background-color: green; |
| } |
| |
| .top-box { |
| position: absolute; |
| left: 200px; |
| top: 1200px; |
| height: 300px; |
| width: 300px; |
| background-color: blue; |
| z-index: 1; |
| |
| } |
| </style> |
| <!-- |
| This test ensures that overlap testing to determine compositing requirements |
| works correctly for layers outside the main frame's viewport. The blue box |
| should appear on top of the green box. |
| --> |
| <div class="composited-box"></div> |
| <div class="top-box"></div> |
| <script> |
| if ('internals' in window) { |
| window.addEventListener('load', () => { |
| // Force a compositing update so it happens while the boxes are off |
| // screen. |
| internals.forceCompositingUpdate(document); |
| |
| // Bring them into view, the z-index order should be correct. |
| window.scrollTo(0, 1500); |
| }); |
| } |
| </script> |
