Javascript , date Field change doesn't work

Question

I want to display the expiration date automatically as soon as I selected a date of issue but it does not work..
<td width="190px" valign="top" class="ms-formlabel">
<H3 class="ms-standardheader"><nobr>StartDate</nobr></H3>
</td>
<td width="400px" valign="top" class="ms-formbody">
<SharePoint:FormField runat="server" id="ff2{$Pos}" ControlMode="New" FieldName="StartDate" __designer:bind="
{ddwrt:DataBind('i',concat('ff2',$Pos),'Value','ValueChanged','ID',ddwrt:EscapeDelims(string(@ID)),'@StartDate')}"/>
<Sha
rePoint:FieldDescription runat="server" id="ff2description{$Pos}" FieldName="StartDate" ControlMode="New"/>
</td>
</tr>
<tr>
<td width="190px" valign="top" class="ms-formlabel">
<H3 class="ms-standardheader"><nobr>EndDate</nobr></H3>
</td>
<td width="400px" valign="top" class="ms-formbody">
<SharePoint:FormField runat="server" id="ff3{$Pos}" ControlMode="New" FieldName="EndDate" __designer:bind="
{ddwrt:DataBind('i',concat('ff3',$Pos),'Value','ValueChanged','ID',ddwrt:EscapeDelims(string(@ID)),'@EndDate')}"/>
<SharePoint:FieldDescription runat="server" id="ff3description{$Pos}" FieldName="EndDate" ControlMode="New"/>
</td>
</tr>
<script type="text/javascript" src="../../JQuery/jquery.js"></script>
<script type="text/javascript">
$(document).ready(function(){
alert (&quot;Test&quot;);
   $(&apos;#ff2&apos;).change(function(){
   alert (&quot;Test&quot;);
       var startVal = $(this).val();
var month = startVal.getMonth();
var day = startVal.getDate();
var year = startVal.getFullYear();
year = year  + 1;
endVal= day+&apos;/&apos;+&apos;month&apos;+&apos;/&apos;+&apos;Year&apos;;
       $(&apos;#ff3&apos;).val(endVal);
</script>

Answer 1

Hi,
Please add the following code into the new form page. You can also add a content editor web part into the new form page and add the code into the web part.
<script src="http://code.jquery.com/jquery-1.10.2.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function () {
$("input[title='Start Date']").blur(function () {
var startVal = $(this).val();
var startDate = new Date(startVal);
var month = startDate.getMonth() + 1;
var day = startDate.getDate();
var year = startDate.getFullYear() + 1;
$("input[title='End Date']").val(month + "/" + day + "/" + year);
</script>
Or here is a thread talk about the similar issue for your reference:
http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/MS-SharePoint/Q_27765240.html
Best Regards
Dennis Guo
TechNet Community Support