js 日期减去月数、天数、周数

    <script language="javascript" type="text/javascript">
        function setStartDate(day) {
            AddTime(day, "d");
        }
        function AddTime(AddDate, types) {
            var EndDate = new Date(document.getElementById("<%=txt_DateEnd.ClientID%>").value.replace(/-/g, "/"));
            var StartDate = new Date(document.getElementById("<%=txt_DateStart.ClientID%>").value.replace(/-/g, "/"));
            switch (types) {
                case "d":
                    StartDate = dateAdd('d', AddDate, EndDate);
                    break;
                case "w":
                    StartDate = dateAdd('w', AddDate, EndDate);
                    break;
                case "m":
                    StartDate = dateAdd('m', AddDate, EndDate);
                    break;
            }
            var m = StartDate.getMonth() + 1;
            var time = StartDate.getFullYear() + "-" + (m < 10 ? '0' + m : m) + "-" + StartDate.getDate();
            document.getElementById("<%=txt_DateStart.ClientID%>").value = time;
        }

        //日期增加函数
        function dateAdd(strInterval, NumDay, dtTmp) {
            if (dtTmp == null | dtTmp == "")
                dtTmp = new Date();
            switch (strInterval) {
                case "h":
                    return new Date(Date.parse(dtTmp) + (3600000 * NumDay));
                case "d":
                    return new Date(Date.parse(dtTmp) + (86400000 * (NumDay + 1)));
                case "w":
                    return new Date(Date.parse(dtTmp) + ((86400000 * 7) * NumDay) + 86400000);
                case "m":
                    return new Date(dtTmp.getFullYear(), (dtTmp.getMonth()) + NumDay, dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
                case "y":
                    return new Date((dtTmp.getFullYear() + NumDay), dtTmp.getMonth(), dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
            }

        }
    </script>

 

    <div>
        <ul  ></asp:TextBox></li></ul>
    </div>