$(function() {
					$("#nights").change(updateDays);
          $("#arrival").change(updateDays).datepicker({
                            dateFormat: 'yy-mm-dd',
                            minDate: 'today',
                            altField: '#fymd',
                            altFormat: 'yymmdd'
                    });
                    $("#departure").change(updateDays).datepicker({
                            dateFormat: 'yy-mm-dd',
                            minDate: 'today +1',
                            altField: '#tymd',
                            altFormat: 'yymmdd'
                    });
            });
			
    function updateDays(){
					var val = $("#fymd").val();
					var ni = parseInt($("#nights").val(),10);//from our select
                    $('#departure').datepicker('option', 'minDate', //Set the minimum date for the departure picker
                            new Date( parseInt(val.substr(0,4),10),//Year, first for digit
                                    parseInt(val.substr(4,2),10)-1,//Month digit 5 and 6 js months are -1
                                    parseInt(val.substr(6),10)+ni));//Day last two digits 7 and 8
                    var days = $("#departure").datepicker( 'getDate' ) - $("#arrival").datepicker( 'getDate' ) 
					if(days>0) $("#days").val(days/(1000*60*60*24));//Convert milliseconds into days
    }