function getEndDate() {
  var now = new Date();
  var days = new Date(now.getFullYear(), now.getMonth()+1, 0).getDate();
  if (now.getDate() < 15)
    return new Date(now.getFullYear(), now.getMonth(), 15);
  else if (now.getDate() == days)
    return new Date(now.getFullYear(), now.getMonth()+1, 15);
  else
    return new Date(now.getFullYear(), now.getMonth(), days);
}

function formatEndDate() {
  var monthNames = ["Jan", "Feb", "Mar", "Apr", "May", "June", "July", "Aug", "Sept", "Oct", "Nov", "Dec"];
  var d = getEndDate();
  return 'Until ' + monthNames[d.getMonth()] + ' ' + d.getDate();
}

$(function(){
  $('#ngg-gallery-1-71 a').lightBox({overlayOpacity: 0});
  $('.end_date').text(formatEndDate());
});