function showDropdownMenu(id) {
  hideDropdownMenus();
  document.getElementById(id).style.display = 'block';
}

function hideDropdownMenu(id) {
  document.getElementById(id).style.display = 'none';
}

function hideDropdownMenus() {
  document.getElementById('menu_dropdown1').style.display = 'none';
  document.getElementById('menu_dropdown2').style.display = 'none';
  document.getElementById('menu_dropdown3').style.display = 'none';
}

function setDrawing(subsite) {
  document.getElementById('drawing').style.backgroundImage = "url('gfx/drawings/"+subsite+".jpg')";
}