function pagina(cat, sez, subsez)
{
	if(cat == '' && subsez == '')
		location.href = "index_esp.php?sez="+sez;
	else
	if(cat == '')
		location.href = "index_esp.php?sez="+sez+"&subsez="+subsez;
	else
	if(subsez == '')
		location.href = "index_esp.php?cat="+cat+"&sez="+sez;
	else	
	location.href = "index_esp.php?cat="+cat+"&sez="+sez+"&subsez="+subsez;	
}