| <!DOCTYPE html> |
| <html> |
| |
| <head> |
| <meta charset="utf-8"> |
| <title> CSS Scroll Snap 2 Test: scroll-start-*</title> |
| <link rel="help" href="https://drafts.csswg.org/css-scroll-snap-2/#scroll-start"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| </head> |
| |
| <body> |
| <style> |
| #scroller { |
| height: 100px; |
| width: 100px; |
| scroll-start: 100px 200px; |
| border: solid 1px black; |
| overflow: scroll; |
| } |
| |
| .spacer { |
| width: 200vw; |
| height: 200vh; |
| border: solid 1px green; |
| } |
| </style> |
| <div id="scroller"> |
| <div class="spacer"></div> |
| </div> |
| <script> |
| async function assertScrollPositionResetOnDisplayNone(scroller) { |
| return new Promise((resolve) => { |
| if (getComputedStyle(scroller)["display"] == "none") { |
| assert_equals(scroller.scrollTop, 0, "scrollTop is reset"); |
| assert_equals(scroller.scrollLeft, 0, "scrollLeft is reset"); |
| resolve(); |
| } else { |
| requestAnimationFrame(async () => { |
| await assertScrollPositionResetOnDisplayNone(scroller); |
| resove(); |
| }); |
| } |
| }); |
| } |
| promise_test(async (t) => { |
| // This tests that toggling the display of a scroller from none to block |
| // scroll-start does not reset the scroller's scroll position. |
| assert_equals(scroller.scrollTop, 100, |
| "scroll-start: <length> sets initial vertical scroll position"); |
| assert_equals(scroller.scrollLeft, 200, |
| "scroll-start: <length> sets initial horizontal scroll position"); |
| |
| // Scroll to somewhere other than scroll-start position. |
| scroller.scrollTop = 200; |
| scroller.scrollLeft = 100; |
| assert_equals(scroller.scrollTop, 200, |
| "vertical scroll position is programmatically adjusted"); |
| assert_equals(scroller.scrollLeft, 100, |
| "horizontal scroll position is programmatically adjusted"); |
| |
| scroller.style.display = "none"; |
| assert_equals(getComputedStyle(scroller)["display"], "none"); |
| |
| await assertScrollPositionResetOnDisplayNone(scroller); |
| |
| scroller.style.display = "block"; |
| assert_equals(getComputedStyle(scroller)["display"], "block"); |
| |
| // Verify that we are again scrolled to the position specified by scroll-start. |
| assert_equals(scroller.scrollTop, 200, |
| "scroll-start is not applied vertically after display toggle"); |
| assert_equals(scroller.scrollLeft, 100, |
| "scroll-start is not applied horizontally after display toggle"); |
| }, "scroll-start does not interfer with recovering saved scroll position " + |
| "after display toggle"); |
| </script> |
| </body> |
