JS实现动态计算两时间差

@model RightMobileSite.Models.Pulse
@{
 ViewBag.Title = "SetDates";
}
<h2>SetDates</h2>
<div>
 @Html.ActionLink("Pulse", "EditPulse", new { pulseId = Model.PulseId }) >
 @Html.Label("Set Dates", "SetDates") >
 @Html.ActionLink("View Pulse", "ViewPulse",new { pulseId=Model.PulseId }) >
 @Html.ActionLink("Select Audience", "Index") >
 @Html.ActionLink("Send for Approval", "Index")
</div>
<script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>
<script src="@Url.Content("~/Scripts/jquery.ui.datetimepicker.js")" type="text/javascript"></script>
<script type="text/javascript">
 <!--
 function dateDiff(interval, date1, date2) {
 var objInterval = { 'D': 1000 * 60 * 60 * 24, 'H': 1000 * 60 * 60, 'M': 1000 * 60, 'S': 1000, 'T': 1 };
 interval = interval.toUpperCase();
 var dt1 = new Date(Date.parse(date1.replace(/-/g, '/')));
 var dt2 = new Date(Date.parse(date2.replace(/-/g, '/')));
 try {
 return Math.round((dt2.getTime() - dt1.getTime()) / eval('objInterval.' + interval));
 }
 catch (e) {
 return e.message;
 }
 }
 function calc() {
 var a = $("input#PulseStartDate").val();
 var b = $("input#PulseFinishDate").val();
 return dateDiff('D',a,b);
 }
 function setRetval() {
 $("input#Duration").val(calc());
 return (true);
 }
 //-->
 $(function () {
 $("input#PulseStartDate").datetimepicker();
 $("input#PulseFinishDate").datetimepicker();
 $("input#Duration").val(calc());
 $("input#PulseStartDate").change(function () {
 setRetval();
 });
 $("input#PulseFinishDate").blur(function () {
 setRetval();
 });
 $("input#PulseFinishDate").change(function () {
 setRetval();
 });
 });
</script>
@using (Html.BeginForm())
{
 @Html.HiddenFor(model => model.PulseId)
 @Html.ValidationSummary(true)
 <fieldset>
 <legend>Pulse</legend>
 
 <div class="editor-label">
 @Html.LabelFor(model => model.PulseStartDate)
 </div>
 <div class="editor-field">
 @Html.EditorFor(model => model.PulseStartDate)
 @Html.ValidationMessageFor(model => model.PulseStartDate)
 </div>
 <div class="editor-label">
 @Html.LabelFor(model => model.PulseFinishDate)
 </div>
 <div class="editor-field">
 @Html.EditorFor(model => model.PulseFinishDate)
 @Html.ValidationMessageFor(model => model.PulseFinishDate)
 </div>
 <div class="editor-label">
 @Html.Label("Pulse Duration")
 </div>
 <div class="editor-label">
 <input type="text" id="Duration"/>
 @Html.Label("days")
 </div>
 <p>
 <input type="submit" value="SetDates" />
 </p>
 </fieldset>
}