<html>
<head>
<style>
body, html {
    height: 100%;
}
.spacer {
    height: 80%;
}
</style>
</head>
<body onload='(parent || opener).childLoad()'>

<div class="spacer"></div>
<div id="content">content</div>
<div class="spacer"></div>

</body>
</html>