สอบถามเรื่องการคำนวณความห่างของวันที่ยืม และวันที่คืน

<script src="http://mattkruse.com/javascript/date/date.js"></script>
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
<script type="text/javascript">
                var minutes = 1000*60;
                var hours = minutes*60;
                var days = hours*24;
                var dxdate1 = getDateFromFormat("02/07/2010", "d/M/y");
                var dxdate2 = getDateFromFormat("02/07/2011", "d/M/y");
                var diff_date = Math.round((dxdate2 - dxdate1)/days);
	  $(function(){
		$("#xtotal").val(diff_date);
		});
</script>
<input type="text" name="xtotal" id="xtotal" value=""> รวมวัน

/**
 * convert string date to date object
 */
var stringToDateObject = function(stringDate) {
	var arrString = stringDate.split("/");
	return new Date(arrString[1] + "/" + arrString[0] + "/" + arrString[2]);
}

/**
 * calculate date between of two dates
 */
var dateBetween = function(startDate , endDate) {
	var sDate = stringToDateObject(startDate);
	var eDate = stringToDateObject(endDate);
	// convert 1 day to milisecound	
	var oneDay = 24 * 60 * 60 * 1000;
	
	return Math.round((eDate.getTime() - sDate.getTime()) / oneDay);
}

/**
 * input format date dd/mm/yy
 * javascrip fomat date mm/dd/yy
 */
console.debug("date between: " + dateBetween("01/02/2010", "01/01/2011"));

<script type="text/javascript">
function CDate(){
  var date1 = document.getElementById('d1').value;
  var date2 = document.getElementById('d2').value;
  date1 = date1.split("/");
  date2 = date2.split("/");
  var sDate = new Date(date1[1]+"/"+date1[0]+"/"+date1[2]);
  var eDate = new Date(date2[1]+"/"+date2[0]+"/"+date2[2]);
  var daysApart = Math.abs(Math.round((sDate-eDate)/86400000));
 document.getElementById('deawx').value = daysApart;
}
</script>

<table width='220' border='1' cellspacing='0' cellpadding='5' align="center">
<tr><td colspan="3" align="center">วันที่ เป็น DD/MM/YYYY เช่น 10/15/1980</td></tr>
<tr>
<td>Starting<br>Date</td>
<td>Ending<br>Date</td>
<td>Total<br>Days</td>
</tr><tr>
<td><input type="text" id="d1" name="d1" value=""> </td>
<td><input type="text" id="d2" name="d2" value=""  onBlur="CDate();" > </td>
<td><input type="text" id="deawx" name="deawx" value="" onFocus="CDate();"> </td>
</tr>
</table>