function rozklikavaciMenu(id_oddeleni)
{
  var pocet;
  var oddeleni = document.getElementById(id_oddeleni);

  if (oddeleni.style.display == 'block')
  {
    oddeleni.style.display = 'none';
  } else
    {
      oddeleni.style.display = 'block';
    }
}
function externalLinks() {
 if (!document.getElementsByTagName) return;
 var anchors = document.getElementsByTagName("a");
 for (var i=0; i<anchors.length; i++) {
   var anchor = anchors[i];
   if (anchor.getAttribute("href") &&
       anchor.getAttribute("rel") == "external")
     anchor.target = "_blank";
 }
}

function zavrit(element)
{
  var zavrit = document.getElementById(element)
  if (zavrit.style.display=='none')
  {
    zavrit.style.display='block';
  } else
    {
      zavrit.style.display='none';
    }
}