function openPrintWindow(FormName, product_id, site_url){
   var link_str = '';
   for(i=0; i<FormName.elements.length; i++){
       if(FormName.elements[i].name.indexOf('option_') !== -1)
          link_str = link_str + FormName.elements[i].value + ',';
   }
   if(link_str !== '') 
      link_str = '&options=' + link_str;

   if(document.getElementById('product_img'))
      img_url = escape(document.getElementById('product_img').src);
   else
      img_url = '';
   
   window.open(site_url + 'product-print.php?product_id=' + product_id + link_str + '&img_url=' + img_url, 'print', 'scrollbars=yes,height=550px,width=500px;');
}