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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /dom/events/scrolling/wheel-event-no-scroll-after-prevent-default.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<head>
<meta charset="utf-8">
<title>Ensure that the calling `preventDefault` on a wheel event prevents a scroll from happening</title>
<link rel="author" title="Martin Robinson" href="mailto:mrobinson@igalia.com">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-actions.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
</head>
<body>
<div id="scroller" style="width: 100px; height: 100px; overflow: scroll; position: relative;">
<div style="position: absolute; width: 100px; height: 500px; background: red;"></div>
<div style="position: absolute; width: 100px; height: 100px; background: green;"></div>
</div>
<script>
function waitForFrame() {
return new Promise(resolve => {
window.requestAnimationFrame(resolve);
});
}
function runTest() {
promise_test(async(t) => {
let wheelEventFired = false;
let scrollEventFired = false;
scroller.addEventListener("wheel", (event) => {
wheelEventFired = true;
event.preventDefault()
});
scroller.addEventListener("scroll", (event) => {
scrollEventFired = true;
event.preventDefault()
});
await new test_driver.Actions()
.addWheel("wheel1")
.scroll(50, 50, 0, 30, {origin: "viewport"})
.pause(1)
.scroll(50, 50, 0, 30, {origin: "viewport"})
.pause(1)
.scroll(50, 50, 0, 30, {origin: "viewport"})
.send();
await waitForFrame();
await waitForFrame();
await waitForFrame();
await waitForFrame();
assert_true(wheelEventFired);
assert_false(scrollEventFired);
}, "When `preventDefault` is called on a WheelEvent, scrolling should be prevented.");
}
window.onload = runTest;
</script>
</body>