Problema select en FF

[scobee]

aqui meto las options...por si os sirve tamb

function init()
{
var htmlCode ="";
for (var i=0;i<year.length;i++)
{
document.getElementById('anyo').innerHTML += "<option selected='selected' value='"+year[i]+"'>"+year[i]+"</option>";
}
htmlCode +="<option selected='selected' value='01'>Enero</option>";
htmlCode +="<option value='02'>Febrero</option>";
htmlCode +="<option value='03'>Marzo</option>";
htmlCode +="<option value='04'>Abril</option>";
htmlCode +="<option value='05'>Mayo</option>";
htmlCode +="<option value='06'>Junio</option>";
htmlCode +="<option value='07'>Julio</option>";
htmlCode +="<option value='08'>Agosto</option>";
htmlCode +="<option value='09'>Septiembre</option>";
htmlCode +="<option value='10'>Octubre</option>";
htmlCode +="<option value='11'>Noviembre</option>";
htmlCode +="<option value='12'>Diciembre</option>";
document.getElementById('meses').innerHTML = htmlCode;
Loaditems();
}