function changeDate(base)
{
  base = ( base ) ? base : '';
  
  var maand = $('select_maand').options[ $('select_maand').selectedIndex ].value;
  var jaar = $('select_jaar').options[ $('select_jaar').selectedIndex ].value;
  var url;
  
  if( jaar != "" && maand != "" )
    url = base +'/nieuws/archief/'+ jaar +'/'+ maand +'/index.html';
  else if( jaar != "" )
    url = base +'/nieuws/archief/'+ jaar +'/index.html';
  else if( maand != "" )
    url = base +'/nieuws/archief/jaar/'+ maand +'/index.html';
  else
    url = base +'/nieuws/archief/alles.html';
  

  window.location = url;
}