var image_opened = new Array;

var change_images = new Array;
change_images['down'] = "fileadmin/templates/images/dropbox_arrow_down.gif";
change_images['up'] = "fileadmin/templates/images/dropbox_arrow_up.gif";

function previmg(wahl){ 
  if (wahl == undefined) {
    return;
  }

  if ($("dropBoxArrow" + wahl) == null) {
    return;
  }

  if (image_opened[wahl] == undefined) {
    image_opened[wahl] = 'up';
  }
  
  image_opened[wahl] = (image_opened[wahl] == 'up') ? 'down' : 'up';

  $("dropBoxArrow" + wahl).src = change_images[image_opened[wahl]];

}