var alreadyOpened=0;

function doShow( doc,id) {
  //alert('show "'+id+'"');
  if (doc.getElementById) {
    var mydiv = doc.getElementById(id);
    mydiv.style.display = 'block';
    mydiv.style.visibility = 'visible';
  }
}

function doShowOnce( doc,id) {
  //alert('once "'+id+'"');
  if (alreadyOpened != 1) {
    alreadyOpened = 1;
    doShow( doc, id)
  }
}

function doHide (doc,id){
  if (doc.getElementById) {
    var mydiv = doc.getElementById(id);
    mydiv.style.display = 'none';
    mydiv.style.visibility = 'hidden';
  }
}