Disable days in jQuery datepicker from http://tokenposts.blogspot.ca/2011/05/jquery-datepicker-disable-specific.html

gistfile1.js

<script type="text/javascript">
var unavailableDates = ["11-1-2013","12-1-2013","13-1-2013"];

function unavailable(date) {
  dmy = date.getDate() + "-" + (date.getMonth()+1) + "-" + date.getFullYear();
  if ($.inArray(dmy, unavailableDates) < 0) {
    return [true,"","Book Now"];
  } else {
    return [false,"","Booked Out"];
  }
}
</script>

<input type="datetime" name="id" id="id" placeholder="YYYY/MM/DD"> 
<script type="text/javascript">
  $('#id').datepicker({dateFormat: 'YYY/MM/DD', changeMonth: true, changeYear: true, yearRange: '+0:+0',beforeShowDay: unavailable});
</script>