function ImageChange( file ) 
{  
  document.getElementById("Obrazek").src = file;
  return false;
}

function loadImage(path)
{
  promenna = new Image();
  promenna.src = path;
}

function showMenu(part)
{
  headerTop = document.getElementById('div_header_top');
  headerTop.style.zIndex = "0";

  var i = 1;
  while ((menupart = document.getElementById('part' + i)))
  {
    menupart.style.visibility = "hidden";
    menupart.style.zIndex = "1";
    i = i + 1;
  }
  
  if (part != 'none')
  {
    headerTop = document.getElementById('div_header_top');
    headerTop.style.zIndex = "30";
    menupart = document.getElementById('part' + part);
    menupart.style.visibility = "visible";
    menupart.style.zIndex = "30";
  }
}