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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /css/cssom-view/smooth-scroll-nonstop.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<html>
<head>
<title>Noop smooth scrolls don't interrupt ongoing smooth scrolls</title>
<meta name="viewport" content="width=device-width,minimum-scale=1,initial-scale=1">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/dom/events/scrolling/scroll_support.js"></script>
</head>
<body>
<style>
.scroller {
height: 200px;
width: 200px;
border: solid 1px black;
background-color: teal;
overflow-y: scroll;
overflow-x: hidden;
position: relative;
}
.box {
height: 50px;
width: 50px;
background-color: purple;
margin-top: 400px;
}
.space {
position: absolute;
height: 200vh;
width: 200vw;
}
</style>
<div id="scroller" class="scroller">
<div class="space"></div>
<div id="box" class="box"></div>
</div>
<script>
const scroller = document.getElementById("scroller");
const box = document.getElementById("box");
async function test_smooth_scroll_nonstop(test, scroll_function, target_offset) {
await waitForScrollReset(test, scroller);
await waitForCompositorCommit(test, scroller);
const scrollend_promise = waitForScrollEndFallbackToDelayWithoutScrollEvent(scroller);
const MAX_NO_MOVE_DURATION_MS = 1000;
let resolve_stuck_promise = null;
const stuck_promise = new Promise((resolve) => {
resolve_stuck_promise = resolve;
});
let last_observed_offset = scroller.scrollTop;
let last_update_time = performance.now;
function run_scroll_function() {
if (scroller.scrollTop != last_observed_offset) {
last_update_time = performance.now();
last_observed_offset = scroller.scrollTop;
} else {
if (performance.now() - last_update_time > MAX_NO_MOVE_DURATION_MS) {
resolve_stuck_promise();
}
}
scroll_function();
}
// Run the scroll function repeatedly.
const id = setInterval(run_scroll_function);
await Promise.any([scrollend_promise, stuck_promise]);
clearInterval(id);
assert_equals(scroller.scrollTop, target_offset,
"scroller reached the target offset");
}
promise_test(async (t) => {
const target_offset = box.offsetTop;
const scroll_function = () => {
scroller.scrollTo({ top: target_offset, behavior: "smooth" });
}
await test_smooth_scroll_nonstop(test, scroll_function, target_offset);
}, "noop scrollTo doesn't interrupt ongoing smooth scroll.");
promise_test(async (t) => {
const target_offset = box.offsetTop;
const scroll_function = () => {
box.scrollIntoView({ block: "start", behavior: "smooth" });
}
await test_smooth_scroll_nonstop(test, scroll_function, target_offset);
}, "noop scrollIntoView doesn't interrupt ongoing smooth scroll.");
</script>
</body>
</html>