function toggleVisibility(item) {
  var x = null;

  if(document.getElementById)
    x = document.getElementById(item).style;
  else if (document.all)
    x = document.all(item).style;
  else if (document.layers)
    x = document.layers[item];

  if (x)
    if (x.display=='none')
      x.display='block'
    else
      x.display='none';  

  if (item != 'menuGroup1') {
    if(document.getElementById)
      x = document.getElementById('menuGroup1').style;
    else if (document.all)
      x = document.all('menuGroup1').style;
    else if (document.layers)
      x = document.layers['menuGroup1'];
    x.display = 'none';
  }
  if (item != 'menuGroup2') {
    if(document.getElementById)
      x = document.getElementById('menuGroup2').style;
    else if (document.all)
      x = document.all('menuGroup2').style;
    else if (document.layers)
      x = document.layers['menuGroup2'];
    x.display = 'none';
  }
  if (item != 'menuGroup3') {
    if(document.getElementById)
      x = document.getElementById('menuGroup3').style;
    else if (document.all)
      x = document.all('menuGroup3').style;
    else if (document.layers)
      x = document.layers['menuGroup3'];
    x.display = 'none';
  }
  if (item != 'menuGroup6') {
    if(document.getElementById)
      x = document.getElementById('menuGroup6').style;
    else if (document.all)
      x = document.all('menuGroup6').style;
    else if (document.layers)
      x = document.layers['menuGroup6'];
    x.display = 'none';
  }
}