| <!DOCTYPE html> |
| <title>position:sticky elements should respect the left constraint</title> |
| <link rel="help" href="https://www.w3.org/TR/css-position-3/#sticky-pos" /> |
| <meta name="assert" content="This test checks that position:sticky elements obey their left anchor after scrolling" /> |
| |
| <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 = setupStickyTest('left', 50); |
| elements.scroller.scrollLeft = 100; |
| const nonStickyLeftX = elements.container.offsetLeft + |
| elements.filler.clientWidth; |
| assert_equals(elements.sticky.offsetLeft, nonStickyLeftX); |
| }, 'before reaching the sticking point the sticky box should not be offset'); |
| |
| test(() => { |
| const elements = setupStickyTest('left', 50); |
| elements.scroller.scrollLeft = 200; |
| |
| // This math actually cancels to sticky.offsetLeft == (scroller.scrollLeft + 50), |
| // but for clarity the calculations are left explicit. |
| const nonStickyLeftX = elements.container.offsetLeft + |
| elements.filler.clientWidth; |
| const targetLeftX = elements.scroller.scrollLeft + 50; |
| const stickyOffset = targetLeftX - nonStickyLeftX; |
| |
| assert_equals(elements.sticky.offsetLeft, nonStickyLeftX + stickyOffset); |
| }, 'after reaching the sticking point the sticky box should be offset'); |
| |
| test(() => { |
| const elements = setupStickyTest('left', 50); |
| elements.scroller.scrollLeft = 300; |
| const maxOffsetInContainer = elements.container.offsetLeft + |
| elements.container.clientWidth - elements.sticky.clientWidth; |
| assert_equals(elements.sticky.offsetLeft, maxOffsetInContainer); |
| }, 'the sticky box should not be pushed outside its containing block'); |
| </script> |