| <!DOCTYPE html> |
| <title>Nested bottom-constrained position:sticky elements should render correctly</title> |
| |
| <link rel="help" href="https://www.w3.org/TR/css-position-3/#sticky-pos" /> |
| <meta name="assert" content="This test checks that nested position:sticky elements with a bottom constraint render correctly" /> |
| |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| |
| <script src="resources/sticky-util.js"></script> |
| |
| <body></body> |
| |
| <script> |
| test(() => { |
| const elements = setupNestedStickyTest('bottom', 25, 35); |
| elements.scroller.scrollTop = 300; |
| const nonStickyTopY = elements.container.offsetTop + |
| elements.filler.clientHeight; |
| assert_equals(elements.sticky.offsetTop, nonStickyTopY); |
| // The inner sticky should not be offset from the outer. |
| const nonStickyInnerTopY = elements.sticky.clientHeight - |
| elements.innerSticky.clientHeight; |
| assert_equals(elements.innerSticky.offsetTop, nonStickyInnerTopY); |
| }, 'before reaching the sticking point, neither sticky box should be offset'); |
| |
| test(() => { |
| const elements = setupNestedStickyTest('bottom', 25, 50); |
| elements.scroller.scrollTop = 150; |
| const nonStickyTopY = elements.container.offsetTop + |
| elements.filler.clientHeight; |
| assert_equals(elements.sticky.offsetTop, nonStickyTopY); |
| assert_equals(elements.innerSticky.offsetTop, 35); |
| }, 'the inner sticky can stick before the outer one if necessary'); |
| |
| test(() => { |
| const elements = setupNestedStickyTest('bottom', 25, 35); |
| elements.scroller.scrollTop = 100; |
| |
| const nonStickyTopY = elements.container.offsetTop + |
| elements.filler.clientHeight; |
| const nonStickyBottomY = nonStickyTopY + elements.sticky.clientHeight; |
| const targetBottomY = elements.scroller.clientHeight + |
| elements.scroller.scrollTop - 25; |
| const stickyOffset = nonStickyBottomY - targetBottomY; |
| assert_equals(elements.sticky.offsetTop, nonStickyTopY - stickyOffset); |
| |
| // The inner sticky has similar math, but its offsetTop is relative to the |
| // sticky element and in this test is (height - the difference between the |
| // top values). |
| assert_equals(elements.innerSticky.offsetTop, 40); |
| }, 'both sticky boxes can be stuck at the same time'); |
| |
| test(() => { |
| const elements = setupNestedStickyTest('bottom', 25, 35); |
| elements.scroller.scrollTop = 0; |
| assert_equals(elements.sticky.offsetTop, elements.container.offsetTop); |
| assert_equals(elements.innerSticky.offsetTop, 0); |
| }, 'neither sticky can escape their containing block'); |
| |
| test(() => { |
| const elements = setupNestedStickyTest('bottom', 25, 500); |
| elements.scroller.scrollTop = 200; |
| // It doesn't matter how big the inner sticky offset is, it cannot escape its |
| // containing block (the outer sticky). |
| assert_equals(elements.innerSticky.offsetTop, 0); |
| }, 'the inner sticky cannot be pushed outside the outer sticky'); |
| </script> |
