function changeLayer(sitecode){
  if(document.getElementById('div_'+sitecode)){
    if ( document.getElementById('div_'+sitecode).style.display == 'none' || document.getElementById('div_'+sitecode).style.display == '') {
      document.getElementById('div_'+sitecode).style.display = 'block';
      var buttons = document.getElementsByName('img_'+sitecode);
      for(var i=0; i<buttons.length; i++){
        buttons[i].src = buttons[i].src.replace('plus', 'minus');
      }
      if(document.getElementById('img_'+sitecode)){
        document.getElementById('img_'+sitecode).src = document.getElementById('img_'+sitecode).src.replace('plus', 'minus');
      }
      if(document.getElementById('a_'+sitecode)){
        document.getElementById('a_'+sitecode).innerHTML = document.getElementById('a_'+sitecode).innerHTML.replace(/anzeigen/g, 'ausblenden');
        document.getElementById('a_'+sitecode).title = document.getElementById('a_'+sitecode).title.replace('anzeigen', 'ausblenden');
      }

      //für die Themenchannel-Darstellung in der Protfolioübersicht
      elemente = Array('zeile', 'td_links', 'td_rechts');
      for(i=1; i<=2; i++){
        for(var j=0; j<elemente.length; j++){
          if(document.getElementById('themenchannel_'+sitecode+'_'+elemente[j]+i)){
            document.getElementById('themenchannel_'+sitecode+'_'+elemente[j]+i).className = document.getElementById('themenchannel_'+sitecode+'_'+elemente[j]+i).className.replace('eingeklappt', 'ausgeklappt');
          }
        }
      }
/*
if(document.getElementById('themenchannel_'+sitecode+'_zeile2')){
        document.getElementById('themenchannel_'+sitecode+'_zeile2').className = document.getElementById('themenchannel_'+sitecode+'_zeile2').className.replace('eingeklappt', 'ausgeklappt');
      }
      */
    }
    else {
      document.getElementById('div_'+sitecode).style.display = 'none';
      var buttons = document.getElementsByName('img_'+sitecode);
      for(var i=0; i<buttons.length; i++){
          buttons[i].src = buttons[i].src.replace('minus', 'plus');
      }
      if(document.getElementById('img_'+sitecode)){
          document.getElementById('img_'+sitecode).src = document.getElementById('img_'+sitecode).src.replace('minus', 'plus');
      }
      if(document.getElementById('a_'+sitecode)){
          document.getElementById('a_'+sitecode).innerHTML = document.getElementById('a_'+sitecode).innerHTML.replace(/ausblenden/g, 'anzeigen');
          document.getElementById('a_'+sitecode).title = document.getElementById('a_'+sitecode).title.replace('ausblenden', 'anzeigen');
      }

      //für die Themenchannel-Darstellung in der Protfolioübersicht
      elemente = Array('zeile', 'td_links', 'td_rechts');
      for(i=1; i<=2; i++){
        for(var j=0; j<elemente.length; j++){
          if(document.getElementById('themenchannel_'+sitecode+'_'+elemente[j]+i)){
            document.getElementById('themenchannel_'+sitecode+'_'+elemente[j]+i).className = document.getElementById('themenchannel_'+sitecode+'_'+elemente[j]+i).className.replace('ausgeklappt', 'eingeklappt');
          }
        }
      }
    }
  }
}