var layerBgDivOrgPos = 0;
var layerDivOrgPos = 0;

var layerVisible = 0;

function showLayer(imgSrcStr)
{
  var layerBgDiv = document.getElementById('layerBgDiv');
  var layerDiv = document.getElementById('layerDiv');

  layerBgDivOrgPos = layerBgDiv.offsetTop;
  layerDivOrgPos = layerDiv.offsetTop;

  var scrollTop = 0;
  if (document.documentElement.scrollTop > 0)
  {
    scrollTop = document.documentElement.scrollTop;
  }
  if (document.body.scrollTop > 0)
  {
    scrollTop = document.body.scrollTop;
  }
  
  layerBgDiv.style.top = (layerBgDivOrgPos + scrollTop) + 'px';
  layerDiv.style.top = (layerDivOrgPos + scrollTop) + 'px';

  layerBgDiv.style.visibility = 'visible';
  layerDiv.style.visibility = 'visible';

  document.popupImg.src = imgSrcStr;

  layerVisible = 1;
}

function hideLayer()
{
  var layerBgDiv = document.getElementById('layerBgDiv');
  var layerDiv = document.getElementById('layerDiv');

  layerBgDiv.style.visibility = 'hidden';
  layerDiv.style.visibility = 'hidden';

  layerBgDiv.style.top = layerBgDivOrgPos;
  layerDiv.style.top = layerDivOrgPos;

  document.popupImg.src = '/images/beeldmerk.jpg';

  layerVisible = 0;
}