var eds=new Array('Ediciones anteriores','2008-09','2008-10','2008-11','2008-12','2009-02','2009-03','2009-04','2009-05');
function paso1(){
s1=document.form1.anterior;
s1.length=0;
for (i=0; i<eds.length; i++){
var ed=eds[i];
var newed = new Option(ed,ed);
s1.options[i] = newed;
}
}