jQuery UI Datepicker: End Date will >= Start Date Solution

$('#check_in_date').datepicker({
dateFormat: 'dd-mm-yy',
minDate: new Date(, , ),
maxDate: '+6m'
});

var $getMinDate = new Date(, , );
function setDef(input, inst) {
var $getCheckOutDate = $('#check_in_date').val();
if($getCheckOutDate != '')
$getMinDate = $getCheckOutDate.split('-');
return {

//minDate: new Date(, , )
minDate: new Date($getMinDate[2], $getMinDate[1]-1, $getMinDate[0])
};
}

$('#check_out_date').datepicker({
dateFormat: 'dd-mm-yy',
maxDate: '+6m',
beforeShow: setDef
});