JavaScript日期时间间隔计算

If you need to validate the date span between the two input dates, I would like to suggest you try the following demo, which works fine on our lab:

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>

    <script type="text/javascript">

        function strDateTime(str) {
            var r = str.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);
            if (r == null) return false;
            var d = new Date(r[1], r[3] - 1, r[4]);
            return (d.getFullYear() == r[1] && (d.getMonth() + 1) == r[3] && d.getDate() == r[4]);
        }

        function btnValidate_onclick() {
            var strfrom = document.getElementById("txtfrom").value;
            var strto = document.getElementById("txtto").value;

            if (!strDateTime(strfrom) && strDateTime(strto)) {
                alert("the date format is not valid");
            }
            else {
                if (DateDiff(strto, strfrom) > 180) {//180 days
                    alert("the date span is too big:" + DateDiff(strto, strfrom));
                    return false;
                }
                else {
                    return true;
                }
            }
        }

        function DateDiff(sDate1, sDate2) {
            var aDate, oDate1, oDate2, iDays
            aDate = sDate1.split("-")
            oDate1 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0])
            aDate = sDate2.split("-")
            oDate2 = new Date(aDate[1] + '-' + aDate[2] + '-' + aDate[0])
            iDays = parseInt(Math.abs(oDate1 - oDate2) / 1000 / 60 / 60 / 24)
            return iDays
        }

    </script>

</head>
<body style="font-family:Calibri; font-size:14px;">
    <form id="form1" runat="server">
    <div>
    </div>
    </form>
    <p>
        From:
        <input id="txtfrom" type="text" />(format: 2009-07-12)</p>
    <p>
        To:
        <input id="txtto" type="text" /></p>
    <p>
        <input id="btnValidate" type="button" value="Validate" onclick="return btnValidate_onclick()" /></p>
</body>
</html>

Thanks.