function showMenu(element) {
  elements = element.getElementsByTagName('div');
  
  for(i = 0; i < elements.length; i++){    
    elements[i].style.visibility = "visible";
  }   
}

function hideMenu(element) {
  elements = element.getElementsByTagName('div');
  
  for(i = 0; i < elements.length; i++){    
    elements[i].style.visibility = "hidden";
  }   
}

function displayPanel(element) {
  elements = element.getElementsByTagName('div');
  
  for(i = 0; i < elements.length; i++){    
    if (elements[i].style.display == "block") {
      elements[i].style.display = "none";
    }
    else {
      elements[i].style.display = "block";
    }
  }   
}