function changeDiv(MenuDiv,MenuChange)
{
  var MenuStyle = getStyleObject(MenuDiv);
  if (MenuStyle != false)
  {
    MenuStyle.display = MenuChange;
  }
}

function hideAll()
{
  changeDiv("CatDisplay1","none");
  changeDiv("CatDisplay2","none");
  changeDiv("CatDisplay3","none");
  changeDiv("CatDisplay4","none");
  changeDiv("CatDisplay5","none");
  changeDiv("CatDisplay6","none");
  changeDiv("CatDisplay7","none");
  changeDiv("CatDisplay8","none");
  changeDiv("CatDisplay9","none");
  changeDiv("CatDisplay10","none"); 
  changeDiv("CatDisplay11","none");
  changeDiv("CatDisplay12","none");
}

function getStyleObject(objectId) {
  if (document.getElementById && document.getElementById(objectId)) {
    return document.getElementById(objectId).style;
  } else if (document.all && document.all(objectId)) {
    return document.all(objectId).style;
  } else {
    return false;
  }
}