两个DateField控件，分别为开始时间和结束时间。当选择完结束时间后，自动计算这两个时间段所间隔的月或天数。

<ext:DateField runat="server" ID="extdate_start_date" LabelStyle=" text-align:right; " FieldLabel="开始时间" Vtype="daterange">
<CustomConfig>
    <ext:ConfigItem Name="endDateField" Value="#{extdate_end_date}" Mode="Value" />
</CustomConfig>
<Listeners>
      <Change Fn="GetBusiDay" />
</Listeners>
</ext:DateField>

<ext:DateField runat="server" ID="extdate_end_date" LabelStyle=" text-align:right; " FieldLabel="结束时间" Vtype="daterange">
     <CustomConfig>
          <ext:ConfigItem Name="startDateField" Value="#{extdate_start_date}" Mode="Value" />
     </CustomConfig>
      <Listeners>
          <Change Fn="GetBusiDay" />
      </Listeners>
</ext:DateField>

Js代码：

function GetBusiDay() {
            if (extdate_start_date.getValue() == "" || extdate_end_date.getValue() == "")
                return;
            var sday = Ext.util.Format.date(extdate_start_date.getValue(), 'Y/m/d');
            var eday = Ext.util.Format.date(extdate_end_date.getValue(), 'Y/m/d');
            var end = new Date(eday);
            var start = new Date(sday);

            var time = end.getTime() - start.getTime();
            var days = parseInt(time / (1000 * 60 * 60 * 24))+1;
            extnumb_busi_day.setValue(days);
        }

注意一定要转换日期格式 //日期格式为yyyy-mm-dd转换成yyyy/mm/dd