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<!DOCTYPE html>
<html class="test-wait">
<meta charset="utf-8">
<link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1822907">
<style>
#inner {
/* Extremely short so that we can just do a double-rAF and
* expect that this transition will have completed: */
transition: opacity 0.01s;
}
</style>
<script>
function setup() {
// Flush style, in case the document hasn't been styled yet:
let origOpacity = getComputedStyle(inner).opacity;
// Trigger the (extremely short) transition, and proceed to next step
// when it finishes.
inner.addEventListener("transitionend", handleTransitionEnd);
inner.style.opacity = "0.8";
}
function handleTransitionEnd(e) {
// Hide & unhide the subtree that contained the transition:
foo.style.contentVisibility = "hidden";
document.documentElement.offsetHeight; // flush layout
foo.style.contentVisibility = "";
// Double-rAF to see if we crash when animations are resampled.
requestAnimationFrame(() => { requestAnimationFrame(finish) });
}
function finish() {
// If we get here, we've succeeded; hooray!
document.documentElement.removeAttribute("class");
}
</script>
<body onload="setup()">
<div id="foo">
Hello
<div id="inner">Inner</div>
</div>
</body>
</html>
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