function swapDivs(hide,show) {
  var icon="I"+hide;
  var main_div="D"+hide;
  var icon_div=document.getElementById(icon);
  if (icon_div) {
    icon_div.style.visibility="hidden";
    icon_div.style.position="absolute";
  }
  document.getElementById(main_div).style.visibility="hidden";
  document.getElementById(main_div).style.position="absolute";
  var icon="I"+show;
  var main_div="D"+show;
  var icon_div=document.getElementById(icon);
  if (icon_div) {
    icon_div.style.visibility="visible";
    icon_div.style.position="relative";
  }
  document.getElementById(main_div).style.visibility="visible";
  document.getElementById(main_div).style.position="relative";
}