<!DOCTYPE html>
<html class="reftest-wait">
<html>
<head>
<style type="text/css">
#abs-pos {
 top: 20px; left: 20px;
 width: 200px;
 background-color: lightgreen;
}
#in-flow-child {
 height: 100px;
 margin-top: 40px;
 margin-bottom: 40px;
 background-color: green;
}
</style>
<script type="text/javascript">
function test() {
 document.getElementById('abs-pos').style.position = 'absolute';
 document.documentElement.removeAttribute('class');
}
document.addEventListener('MozReftestInvalidate', test);
</script>
</head>
<body>
<div id="abs-pos">
 <div id="in-flow-child"></div>
</div>
</body>
</html>