function getInnerHeight() {

	var myHeight = 0;
	
	if(typeof( window.innerWidth ) == 'number')
	{
    	//Non-IE
		myHeight = window.innerHeight;
  	} 
	else if(document.documentElement && document.documentElement.clientHeight)
	{
    	//IE 6+ in 'standards compliant mode'
		myHeight = document.documentElement.clientHeight;
  	}
	else if(document.body && document.body.clientHeight)
	{
		//
		myHeight = document.body.clientHeight;
  	}
  	return myHeight;
}

function center_vertical(elementId, elementHeight)
{
	myTop = ( Math.round((getInnerHeight() - elementHeight)/2) - 20);
	if(myTop < 0) myTop = 0;
	myElement = document.getElementById(elementId);
	//myElement.style.padding = myTop + 'px 0px 0px 0px';
	myElement.style.top = myTop + 'px';
}