gecko/layout/reftests/margin-collapsing/column-sibling-1a-dyn.html

<!DOCTYPE html>
<html class="reftest-wait">
<head>
<style type="text/css">
#block1, #block2 {
 height: 20px;
 background-color: orange;
}
#block1 {
 margin-bottom: 10px;
}
#multi-column {
 display: none;
 -moz-column-count: 1;
 column-count: 1;
 height: 20px;
 margin: 20px 0;
 background-color: blue;
}
#block2 {
 margin-top: 10px;
}
</style>
<script type="text/javascript">
function test() {
 document.getElementById('multi-column').style.display = 'block';
 document.documentElement.removeAttribute('class');
}
document.addEventListener('MozReftestInvalidate', test, false);
</script>
</head>
<body>
<div id="block1"></div>
<div id="multi-column"></div>
<div id="block2"></div>
</body>
</html>