Source code
Revision control
Copy as Markdown
Other Tools
Test Info:
- This WPT test may be referenced by the following Test IDs:
- /css/css-scroll-anchoring/adjustments-in-scroll-event-handler.tentative.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta name="viewport" content="width=device-width">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
body { margin: 0 }
.content {
height: 200px;
background: lightblue;
}
.spacer {
height: 300vh;
}
</style>
<div class="content"></div>
<div class="content" style="background: green"></div>
<div class="spacer"></div>
<script>
const anchor = document.querySelectorAll(".content")[1];
const t = async_test("Scroll adjustments happen even if it's triggered from scroll event listeners");
window.addEventListener("scroll", t.step_func(function() {
// Forcibly flush layout, this will flush the pending the node insertion.
let scrollPosition = window.scrollY;
requestAnimationFrame(t.step_func(function() {
requestAnimationFrame(t.step_func(function() {
assert_equals(window.scrollY, 400);
t.done();
}));
}));
}), { once: true });
window.onload = t.step_func(function() {
requestAnimationFrame(t.step_func(function() {
// Scroll to the anchor node in a requestAnimationFrame callback so that
// it queues a scroll event which will be fired in the next event loop.
anchor.scrollIntoView({ behavior: "instant" });
// Then in a setTimeout callback insert an element just right before the
// anchor node, it will run before firing the scroll event.
t.step_timeout(function() {
const content = document.createElement("div");
content.classList.add("content");
content.style.background = "red";
anchor.before(content);
}, 0);
}));
});
</script>