| <!DOCTYPE html> |
| <meta charset="utf-8"> |
| <title>CSS Test: scroll tracking for ::scroll-marker </title> |
| <link rel="help" href="https://drafts.csswg.org/css-overflow-5/#scroll-container-scroll"> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| <script src="/css/css-transitions/support/helper.js"></script> |
| <script src="/dom/events/scrolling/scroll_support.js"></script> |
| <style> |
| #scroller { |
| overflow: scroll; |
| scroll-marker-group: before; |
| height: 100px; |
| scroll-behavior: smooth; |
| background-color: purple; |
| border: solid 1px black; |
| } |
| |
| #scroller::scroll-marker-group { |
| border: 3px solid black; |
| display: flex; |
| width: 100px; |
| height: 20px; |
| } |
| |
| #scroller div { |
| width: 100px; |
| height: 100px; |
| } |
| |
| #scroller div::scroll-marker { |
| content: ''; |
| background-color: red; |
| display: inline-flex; |
| width: 10px; |
| height: 10px; |
| border-radius: 50%; |
| } |
| |
| #scroller div::scroll-marker:target-current { |
| background-color: green; |
| } |
| </style> |
| <div id='scroller'> |
| <div id="initial"></div> |
| <div class="inbetween"></div> |
| <div class="inbetween"></div> |
| <div class="inbetween"></div> |
| <div id='target'></div> |
| </div> |
| <script> |
| const inbetweens = scroller.querySelectorAll(".inbetween"); |
| const GREEN = "rgb(0, 128, 0)"; |
| const RED = "rgb(255, 0, 0)"; |
| |
| function assertPseudoElementProperty(originatingElement, pseudoType, backgroundColor) { |
| const pseudoStyle = getComputedStyle(originatingElement, pseudoType); |
| const pseudoBackgroundColor = pseudoStyle.getPropertyValue('background-color'); |
| assert_equals(pseudoBackgroundColor, backgroundColor, pseudoType + |
| " background-color should be " + backgroundColor.toString() + |
| " but was " + pseudoBackgroundColor.toString()); |
| } |
| |
| let marker_change_observed = false; |
| function watchFrames() { |
| const initialPseudoStyle = getComputedStyle(initial, "::scroll-marker"); |
| const initialPseudoBackgroundColor = |
| initialPseudoStyle.getPropertyValue('background-color'); |
| |
| if (initialPseudoBackgroundColor === RED) { |
| marker_change_observed = true; |
| } else { |
| assert_false(marker_change_observed); |
| assert_equals(initialPseudoBackgroundColor, GREEN, |
| "initial scroll-marker is initially green"); |
| } |
| |
| // All the markers in between should always be red. |
| for (const inbetween of inbetweens) { |
| assertPseudoElementProperty(inbetween, "::scroll-marker", RED); |
| } |
| |
| // target should become and stay the selected scroll-marker. |
| assertPseudoElementProperty(target, "::scroll-marker", |
| marker_change_observed ? GREEN : RED); |
| |
| requestAnimationFrame(watchFrames); |
| } |
| |
| function scrollPromise() { |
| return new Promise((resolve) => { |
| // For browsers that don't support the scrollend event, just wait till |
| // at least half the expected scroll is done. |
| if (document.scrollingElement.onscrollend === undefined) { |
| function scrollListener() { |
| const max_scroll_offset = |
| scroller.scrollHeight - scroller.ClientHeight; |
| if (scroller.scrollTop >= max_scroll_offset / 2) { |
| scroller.removeEventListener(scrollListener); |
| resolve(); |
| } |
| } |
| scroller.addEventListener("scroll", scrollListener); |
| } else { |
| function scrollEndListener() { |
| scroller.removeEventListener("scrollend", scrollEndListener); |
| resolve(); |
| } |
| scroller.addEventListener("scrollend", scrollEndListener); |
| } |
| }); |
| }; |
| |
| promise_test(async (t) => { |
| await waitForAnimationFrames(2); |
| assertPseudoElementProperty(initial, "::scroll-marker", GREEN); |
| assertPseudoElementProperty(target, "::scroll-marker", RED); |
| |
| function changeDivWidths() { |
| const WIDTH1 = "100px"; |
| const WIDTH2 = "200px"; |
| const divs = scroller.querySelectorAll("div"); |
| const current_width = divs[0].style.width; |
| const target_width = current_width === WIDTH1 ? WIDTH2 : WIDTH1; |
| divs.forEach(div => { div.style.width = target_width; }); |
| } |
| |
| // Add a scroll listener which will trigger a layout change. |
| // Despite the layout change, the user agent should only select |
| // the eventual scroll position of the ongoing smooth scrollIntoView. |
| scroller.addEventListener("scroll", changeDivWidths); |
| |
| const scroll_promise = scrollPromise(); |
| watchFrames(); |
| target.scrollIntoView({ behavior: "smooth" }); |
| await scroll_promise; |
| |
| assertPseudoElementProperty(initial, "::scroll-marker", RED); |
| assertPseudoElementProperty(target, "::scroll-marker", GREEN); |
| }, "The selected ::scroll-marker is updated using the eventual scroll " + |
| "position for a programmatic scroll"); |
| </script> |
