function openBG()
{
	a = document.getElementById('outer').offsetHeight;
	h = a+70; 												/* de content heeft een padding van 70px aan de onderkant*/
	document.getElementById('overlay').style.display = 'block';
	document.getElementById('overlay').style.height = h+'px';
}

function closeBG()
{
	document.getElementById('overlay').style.display = 'none';
	document.getElementById('popup').style.display = 'none';
}


function openLayer(imgurl) {
	document.getElementById('popupImage').src = imgurl;
    
    openBG();
    
    
// positie zetten!    
	if (window.innerHeight)
	{
		  pos = window.pageYOffset;
	}
	else if (document.documentElement && document.documentElement.scrollTop)
	{
		pos = document.documentElement.scrollTop;
	}
	else if (document.body)
	{
		  pos = document.body.scrollTop;
	}
	document.getElementById('popup').style.top = pos+100+'px';
	document.getElementById('popup').style.display = 'block';
	
	
    
}