function filter_by_month(month){
    $('#filter_month').val(month);
    submit_filter_form();
}
function filter_by_year(year){
    $('#filter_year').val(year);
    submit_filter_form();
}

function submit_filter_form(){
    $action = $("#NewsFilterForm").attr("action") + "year/" + $('#filter_year').val() + "/month/" +$('#filter_month').val();
    $("#NewsFilterForm").attr("action", $action);
    $("#NewsFilterForm").submit(); 
}