var curLayer = "i00";
var curInfo = "";
var objectsOK = false;

function show(layer)
{
  if(document.getElementById(layer))
    document.getElementById(layer).style.visibility = "visible";
}

function hide(layer)
{
  if(document.getElementById(layer))
    document.getElementById(layer).style.visibility = "hidden";
}

function changeImage(layer, oName, imgObj)
{
  if (objectsOK)
    if(document.images)
  		document.images[oName].src = eval(imgObj+".src");
}

function changeImageCond(layer, oName, imgObj)
{
  if (oName != curInfo)
    changeImage(layer, oName, imgObj);  
}

function switchTo(layer)
{
  if (objectsOK)
  {
    hide(curLayer);
    show(layer);
    curLayer = layer;
  }
  else
  {
    alert("noch nicht alle bilder geladen");
    document.location.href = document.location.href;
  }
}

function switchToInfo(layer)
{
  switchTo(layer);
  if(curInfo != "" && curInfo != "info" + layer.slice(1,3))
    changeImage('programm', curInfo, 'info_img');
  curInfo = "info" + layer.slice(1,3);
}

function displayProg()
{
  if(document.getElementById("archiv"))
  {
    form = document.getElementById("archiv");
    monat = form.monat.value;
    jahr = form.jahr.value;
  }
  
  jetzt = new Date();
  aktjahr = jetzt.getYear();

  if(aktjahr < 1900) aktjahr+=1900;
  aktmonat = jetzt.getMonth() + 1;

  if (jahr == "2000" && monat < "03")
    alert ("Kein Archiveintrag verfügbar.");
  else if (jahr > aktjahr || (jahr == aktjahr && monat > aktmonat))
    alert ("Kein Archiveintrag verfügbar.");
  else if (jahr == aktjahr && monat > aktmonat - 1)
    alert ("Kein Archiveintrag verfügbar.");  
  else
  {
    fileName = "";
    parts = document.location.href.split("/");
    if (parts[parts.length-2] != "archiv")
      fileName = "archiv/"
    fileName = fileName + "programm_" + jahr + monat + ".html";
    location.href = fileName;
  }
}

function openPopUp(URL)
{
  wndPopUp = self.open(URL,"wndPopUp","width=600,height=550");
}