<!doctype HTML>
<html>
<meta charset="utf8">
<title>Content Visibility: first visibility determination happens before resize observer.</title>
<link rel="author" title="Vladimir Levin" href="mailto:[email protected]">
<link rel="help" href="https://drafts.csswg.org/css-contain/#content-visibility">
<meta name="assert" content="first visibility determination happens before resize observer">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<style>
#target {
content-visibility: auto;
contain-intrinsic-size: 10px;
}
#child {
height: 100px;
}
</style>
<div id=container></div>
<script>
promise_test(t => new Promise(async (resolve, reject) => {
requestAnimationFrame(() => {
let target = document.createElement("div");
target.id = "target";
let child = document.createElement("div");
child.id = "child";
target.appendChild(child);
const resizeObserver = new ResizeObserver((entries) => {
for (const entry of entries) {
if (entry.contentBoxSize) {
if (entry.contentBoxSize[0].blockSize == 100) {
resolve();
return;
} else {
reject(`unexpected size ${entry.contentBoxSize[0].blockSize}`);
return;
}
}
}
reject("no content boxes or no entries");
});
container.appendChild(target);
resizeObserver.observe(target);
});
}), "Target is sized and laid out before resize observer");
</script>
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