<script type="text/javascript">
var screenWidth,screenHeight;
if (self.innerHeight) // all except Internet Explorer
{
screenWidth = self.innerWidth;
screenHeight = self.innerHeight;
}
else if (document.documentElement && document.documentElement.clientHeight)
// Internet Explorer 6 Strict Mode
{
screenWidth = document.documentElement.clientWidth;
screenHeight = document.documentElement.clientHeight;
}
else if (document.body) // other Internet Explorers
{
screenWidth = document.body.clientWidth;
screenHeight = document.body.clientHeight;
}
var SilverLightAppHeight = screenHeight - /* insert banner height here */;
</script>
later on when you need to adjust the size of your form
<script type="text/javascript">
document.getElementById('silverlightform').style.height = SilverLightAppHeight;
</script>