function crea_news(num,classe) {
   if (classe == null) {
      classe='lista1';
   }
   document.writeln('<ul class="'+classe+'">');
   var stop=max_news - num;
   cont=max_news - 1;
   while (cont>=stop) {
      document.writeln('<li>'+news[cont].date+': '+news[cont].text+'</li>');
      cont--;
   }
   document.writeln('</ul>');
}