var bannersLarge = [ [ '/uploads/bannervacaturesgroot-4.jpg', 'http://www.bni.nl/voor-interieurarchitecten/vraag-en-aanbod/vacatures.php' ] ];
var bannersSmall = [];

var indexLarge = 0, indexSmall = 0, intervalId, interval = 15 * 1000, html;

function rotate()
{ var imageUrl, targetUrl, marginStyle;

  if ($('#sidebar #banner_area').length) $('#sidebar #banner_area').remove();

  html = '';

  if (indexLarge == bannersLarge.length) indexLarge = 0;
  if (indexSmall == bannersSmall.length) indexSmall = 0;

  if (bannersLarge.length)
  { imageUrl = bannersLarge[indexLarge][0];
    targetUrl = bannersLarge[indexLarge][1];

    html += '<div style="font-size: 0;"><a href="' + targetUrl + '" title="" rel="nofollow" style="font-size: 0; line-height: 0;"><img src="' + imageUrl + '" width="200" height="210" alt="" /></a></div>';
  }

  if (bannersSmall.length)
  { 

    imageUrl = bannersSmall[indexSmall][0];
    targetUrl = bannersSmall[indexSmall][1];

    if (bannersLarge.length) marginStyle = ' margin-top: 10px;';

    html += '<div style="font-size: 0;' + marginStyle + '"><a href="' + targetUrl + '" title="" rel="nofollow" style="font-size: 0; line-height: 0;"><img src="' + imageUrl + '" width="200" height="100" alt="" /></a></div>';
  }

  if (html.length)
  { if ($('#sidebar').find('*').size())
    { // alert('sidebar html: ' + $('#sidebar').html());
      html = '<div class="sidebar_spacer"></div>' + html;
    }
    html = '<div id="banner_area">' + html + '</div>';
  }

  $('#sidebar').append(html);

  indexLarge++;
  indexSmall++;
}

$(document).ready(function ()
  { rotate();

    intervalId = window.setInterval('rotate();', interval);
  }
);