function showSubMenu(target, source) {
   target.style.left    = (source.offsetLeft + 50) + 'px';
   target.style.top     = (source.offsetTop + source.offsetHeight - 2) + 'px';
   target.style.display = 'block';
}

function openPopupWindow() {
   vangstWindow = Popup.open('content/html/vangstgebieden.' + currentLocale + '.html', 'vangstgebieden', 530, 350, []);
   vangstWindow.focus();
}

function updateScrollToTop() {
   if (window.pageYOffset && window.pageYOffset > 0) {
      document.getElementById('totop').style.display = 'block';
   } else if (document.documentElement.scrollTop && document.documentElement.scrollTop > 0) {
      document.getElementById('totop').style.display = 'block';
      document.getElementById('totop').style.top = ( document.documentElement.scrollTop + document.documentElement.clientHeight - 40 ) + 'px';
   } else {
      document.getElementById('totop').style.display = 'none';
   }
}