var meses = new Array("Enero",
 					   "Febrero",
					   "Marzo",
					   "Abril",
					   "Mayo",
					   "Junio",
					   "Julio",
					   "Agosto",
					   "Septiembre",
					   "Octubre",
					   "Noviembre",
					   "Diciembre");

function options(y){
		 		var    ii,jj=meses.length;
				var     l = 0;
				var   mrk = /\./i
				var     d = new Date();
				var    ix;   	
				var   mes=11;
				var   year;
				var   tope=2004;
				
				if(y==-1 || y=="undefined"){
				  year= d.getFullYear().toString();
				  mes  = d.getMonth();
				 }
				 else 
				      year=y.toString();
				do{
				   name=(meses[mes]+year+".htm").toUpperCase();
				   ix=mes;
				   ii=0;
				   do{	
				      aux=op[ii].toUpperCase();
				      if(aux.search(name)!=-1)
					     break;
					   ii++;	 
				   }while(ii<op.length);

				   name=meses[ix]+" / "+year; 

					if(!mes){
					    mes=11;
						year=(d.getFullYear()-1).toString();
				    }
					else
					    mes--;	
						
				   if(ii>=op.length)
				      continue;
				   
				   document.Formula.Selector[l]=new Option(name,"../asp/genesis.asp?TB0=PLANTILLAS&TB1=MES&TB2=/Mes/"+aux+"&TB3="+y, false );

				   if(actual.search(aux)!=-1)
				  	      document.Formula.Selector.options[l].selected=1;
				   l++;		 
				   }while(--jj);

				   jj=d.getFullYear()-1;
				   l=1;
				   while(jj>=tope){
  				  	      document.Formula.year[l]=new Option(jj,"../asp/genesis.asp?TB0=PLANTILLAS&TB1=MES&TB2=/Mes/Diciembre"+jj+".htm&TB3="+jj,false);
						  if(jj==y)		   
				            document.Formula.year.options[l].selected=1;
 				   		 l++;
						 jj--;
				   }
				   
}