$(function() {
  $('#payment_sent_on_today').click(function() {
    var today = new Date();
    $('#billable_payment_sent_on_1i').val(today.getFullYear());
    $('#billable_payment_sent_on_2i').val(today.getMonth() + 1);
    $('#billable_payment_sent_on_3i').val(today.getDate());
    return false;
  });
});