<html>
<head>
<style>
div {
display: -moz-box;
display: -webkit-box;
display: box;
width: 100px;
height: 100px;
}
div.outer {
background-color:red;
}
div.inner {
background-color:green;
-moz-box-flex: 1;
-webkit-box-flex: 1;
box-flex: 1;
width:10px;
height:100px;
display: block;
}
</style>
</head>
<body>
<p>You should see a single 100x100 green square below. If you see any red, then
the test has failed.</p>
<div class="outer">
<div class="inner"></div>
</div>
</body>