var visibleDiv = "div01";

function showDiv(idVariable)
{
  document.getElementById(idVariable).style.display = 'block';
  document.visibleDiv = idVariable;
}

function hideDiv(idVariable)
{
  document.getElementById(idVariable).style.display = 'none';
  document.getElementById(visibleDiv).style.display = 'none';
}

function HideAndShowDiv(idHide, idShow, idBannerImg)
{
  var newImg = new Image();
  var imgBanner = document.getElementById('BannerIMG');

  if (idBannerImg != '') {
    newImg.src = '../pics/' + idBannerImg + '.jpg';
  } else {
    newImg.src = '../pics/banner_01.jpg';
  };

  imgBanner.src    = newImg.src;
  imgBanner.height = 150;
  imgBanner.width  = 450;

  document.getElementById(idHide).style.display = 'none';
  document.getElementById(idShow).style.display = 'block';
  visibleDiv = idShow;

}