function swapZIndex(id,id2){
      document.getElementById(id).style.visibility='visible';
      document.getElementById(id2).style.visibility='hidden';
      if(id == 'nieuws_tekst'){
        document.getElementById('nieuwsbutton').style.backgroundColor='#e3e3e3';
        document.getElementById('nieuwsbutton').style.color='#000000';
        document.getElementById('archiefbutton').style.backgroundColor='#000000';
        document.getElementById('archiefbutton').style.color='#ffffff';
      }else if(id == 'nieuwsarchief_tekst'){
        document.getElementById('archiefbutton').style.backgroundColor='#e3e3e3';
        document.getElementById('archiefbutton').style.color='#000000';
        document.getElementById('nieuwsbutton').style.backgroundColor='#000000';
        document.getElementById('nieuwsbutton').style.color='#ffffff';
      }else if(id == 'maandagenda_tekst'){
        document.getElementById('maandagendabutton').style.backgroundColor='#e3e3e3';
        document.getElementById('maandagendabutton').style.color='#000000';
        document.getElementById('agendabutton').style.backgroundColor='#000000';
        document.getElementById('agendabutton').style.color='#ffffff';
      }else if(id == 'agenda_tekst'){
        document.getElementById('agendabutton').style.backgroundColor='#e3e3e3';
        document.getElementById('agendabutton').style.color='#000000';
        document.getElementById('maandagendabutton').style.backgroundColor='#000000';
        document.getElementById('maandagendabutton').style.color='#ffffff';
      }
}