สอบถามวิธี ไม่ให้วันที่สิ้นสุด น้อยกว่า วันที่เริ่มต้น

<script type="text/javascript">

$(function(){

	var startDateTextBox = $('#dateStart');
	var endDateTextBox = $('#dateEnd');

	startDateTextBox.datepicker({ 
		dateFormat: 'dd-M-yy',
		onClose: function(dateText, inst) {
			if (endDateTextBox.val() != '') {
				var testStartDate = startDateTextBox.datetimepicker('getDate');
				var testEndDate = endDateTextBox.datetimepicker('getDate');
				if (testStartDate > testEndDate)
					endDateTextBox.datetimepicker('setDate', testStartDate);
			}
			else {
				endDateTextBox.val(dateText);
			}
		},
		onSelect: function (selectedDateTime){
			endDateTextBox.datetimepicker('option', 'minDate', startDateTextBox.datetimepicker('getDate') );
		}
	});
	endDateTextBox.datepicker({ 
		dateFormat: 'dd-M-yy',
		onClose: function(dateText, inst) {
			if (startDateTextBox.val() != '') {
				var testStartDate = startDateTextBox.datetimepicker('getDate');
				var testEndDate = endDateTextBox.datetimepicker('getDate');
				if (testStartDate > testEndDate)
					startDateTextBox.datetimepicker('setDate', testEndDate);
			}
			else {
				startDateTextBox.val(dateText);
			}
		},
		onSelect: function (selectedDateTime){
			startDateTextBox.datetimepicker('option', 'maxDate', endDateTextBox.datetimepicker('getDate') );
		}
	});

});

</script>
Start Date : <input type="text" name="dateStart" id="dateStart" value="" /> 
End Date : <input type="text" name="dateEnd" id="dateEnd" value="" /> 

 <link rel="stylesheet" href="css/datepicker.css">
 <script src="js/bootstrap-datepicker-thai.js"></script>
<script type="text/javascript">  
       var startDate = new Date('01/01/2009');
	   var FromEndDate = new Date();
	   var ToEndDate = new Date();

	   ToEndDate.setDate(ToEndDate.getDate()+365);

	   $('#start').datepicker({
    		format: 'yyyy-mm-dd',
    		weekStart: 1,
    		startDate: '01/01/2009',
   	 		endDate: FromEndDate, 
   	 		autoclose: true
	})
    .on('changeDate', function(selected){
        startDate = new Date(selected.date.valueOf());
        startDate.setDate(startDate.getDate(new Date(selected.date.valueOf())));
        $('#end').datepicker('setStartDate', startDate);
    }); 
		$('#end').datepicker({
        	format: 'yyyy-mm-dd',
        	weekStart: 1,
        	startDate: startDate,
        	endDate: ToEndDate,
        	autoclose: true
    })
    .on('changeDate', function(selected){
        FromEndDate = new Date(selected.date.valueOf());
        FromEndDate.setDate(FromEndDate.getDate(new Date(selected.date.valueOf())));
        $('#start').datepicker('setEndDate', FromEndDate);
    });
    </script>