function getElemRefs(id) {
	var el = (document.getElementById)? document.getElementById(id): (document.all)? document.all[id]: (document.layers)? document.layers[id]: null;
	if (el) el.css = (el.style)? el.style: el;
	return el;
}

function showLayer(id) {
  var lyr = getElemRefs(id);
  if (lyr && lyr.css) lyr.css.visibility = "visible";
}

function hideLayer(id) {
  var lyr = getElemRefs(id);
  if (lyr && lyr.css) lyr.css.visibility = "collapse";
}

function swapLayers(id) {
  var lyr = getElemRefs(id);  
//  if (lyr && lyr.css && lyr.css.visibility=="collapse"){
  if (lyr && lyr.css && lyr.css.display=="none"){
//    lyr.css.visibility = "visible";
    lyr.css.display = '';
//  } else if (lyr && lyr.css && lyr.css.visibility=="visible"){
  } else if (lyr && lyr.css && lyr.css.display==''){
//    lyr.css.visibility = "collapse";
    lyr.css.display = "none";
  }
}