function toggle (switcher) { // followed by list of IDs of elements to toggle

  if(! document.getElementById)
    throw complainting("Your browser's JavaScript system is too old.  ",
       "Upgrade at getfirefox.com !");

  for(var i = 1; i < arguments.length; i++) {
    var element
    var el = document.getElementById( arguments[i] );
    if(!el) throw complaining("Failed to find element with id='"
     + arguments[i] + "' in " + document.location );
    var behidden;

    if(  (el.style.display || 'block') == 'block')
         { el.style.display =  'block' ; behidden = true;  } 
    else { el.style.display =  'block'; behidden = false;  }
  }

  return false;
}
function HideContent(d) {
document.getElementById(d).style.display = "none";
}
function ShowContent(d) {
document.getElementById(d).style.display = "block";
}
function ReverseDisplay(d) {
if(document.getElementById(d).style.display == "none") { document.getElementById(d).style.display = "block"; }
else { document.getElementById(d).style.display = "none"; }
}