function getcookie(name) {
  var dc = document.cookie;
  var prefix = name + "=";
  var begin = dc.indexOf("; " + prefix);
  if (begin == -1) {
    begin = dc.indexOf(prefix);
    if (begin != 0) return null;
  } else
    begin += 2;
  var end = document.cookie.indexOf(";", begin);
  if (end == -1)
    end = dc.length;
  return unescape(dc.substring(begin + prefix.length, end));
}
function masuno(){
         var valor=0;
                          valor = getcookie('libros');
                          valor++  ;
                          document.cookie = "libros=" + escape(valor)  ;
    document.fr_alacesta.action = "/tienda/alacesta.php";
    document.fr_alacesta.submit();
}
function deletecookie(name, path, domain) {

                         

  if (getcookie(name)) {
    document.cookie = name + "=" + 
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}