function showHide(block_id)
 {
   var bild = 'img_' + block_id;
   if(document.getElementById(block_id).style.display == 'none')
   {
     document.getElementById(block_id).style.display = '';
     document.getElementById(bild).src = '/alpiger/skin/frontend/default/Alpiger-Theme/images/icons/minus.gif';
    }
   else
   {
     document.getElementById(block_id).style.display = 'none';
     document.getElementById(bild).src = '/alpiger/skin/frontend/default/Alpiger-Theme/images/icons/plus.gif';
   }
 }