var popy1 = 150;   // change the # on the left to adjust the Y co-ordinate
(document.getElementById) ? dom = true : dom = false;

function hideItdark() {
  if (dom) {document.getElementById("darklayer").style.visibility='hidden';}
  if (document.layers) {document.layers["darklayer"].visibility='hide';}
}

function showItdark() {
  if (dom) {document.getElementById("darklayer").style.visibility='visible';}
  if (document.layers) {document.layers["darklayer"].visibility='show';}
}

function placeItdark() {
  if (dom && !document.all) {document.getElementById("darklayer").style.top = window.pageYOffset + (window.innerHeight - (window.innerHeight))}
  if (document.layers) {document.layers["darklayer"].top = window.pageYOffset + (window.innerHeight - (window.innerHeight))}
  if (document.all) {document.all["darklayer"].style.top = document.body.scrollTop + (document.body.clientHeight - (document.body.clientHeight));}
  window.setTimeout("placeItdark()", 10); }