js 获取据当前时间n天前的时间

<script type="text/javascript">

        function getLastDate() {

            var date = new Date();

            var month = date.getMonth() + 1;

            var day = date.getDate();

            var hh = date.getHours();

            var mm = date.getMinutes();

            var ss = date.getSeconds();

            var year = date.getFullYear();

            alert(year);

           

            var ym;

            var year1;

            day = day - 10;

            if (day <= 0) {

                day = mygetday(day, month, year);

                var months = mygetmonth(month);

                ym = months.split(",");

                year1 = ym[0];

                day = FormatDate(day);

                month = FormatDate(ym[1]);

                return year1 + "-" + month + "-" + day + "&nbsp;" + hh + ":" + mm + ":" + ss;

            }

            else {

                return year + "-" + month + "-" + day + "&nbsp;" + hh + ":" + mm + ":" + ss;

            }



        }



        // 获取某一天的日期

        function mygetday(day, month, year) {

            var daynum = 30;

            if (month == 2 || month == 4 || month == 6 || month == 8 || month == 9

            || month == 1 || month == 11) {

                daynum = 31;

            } else if (month == 3) {

                if (year % 4 == 0) {

                    daynum = 29;

                } else {

                    daynum = 28;

                }

            }

            day = daynum + day;

            return day;

        }

        // 获取某一天的月份

        function mygetmonth(month) {

            var year = new Date().getFullYear();

            if (month == 1) {

                month = 12;

                year = year - 1;

            } else {

                month = month - 1;

            }

            return year + "," + month;

        }

        function FormatDate(d) {

            if (d.toString().length == 1) {

                d = "0" + d;

            }

            return d;

        }

        $(function () {

            $('#birthday').datetimebox('setValue', getLastDate());

        });



    </script>





 <script type="text/javascript">

        function getLastDate() {

            var date = new Date(); //获取当前时间

            var month = date.getMonth() + 1;

            var day = date.getDate();

            var hh = date.getHours();

            var mm = date.getMinutes();

            var ss = date.getSeconds();

            var year = date.getFullYear();

            alert(year);

           

            var ym;

            var year1;

            day = day - 10; //获取十天前的时间

            if (day <= 0) {

                day = mygetday(day, month, year);

                var months = mygetmonth(month);

                ym = months.split(",");

                year1 = ym[0];

                day = FormatDate(day);

                month = FormatDate(ym[1]);

                return year1 + "-" + month + "-" + day + "&nbsp;" + hh + ":" + mm + ":" + ss;

            }

            else {

                return year + "-" + month + "-" + day + "&nbsp;" + hh + ":" + mm + ":" + ss;

            }



        }



        // 获取某一天的日期

        function mygetday(day, month, year) {

            var daynum = 30;

            if (month == 2 || month == 4 || month == 6 || month == 8 || month == 9

            || month == 1 || month == 11) {

                daynum = 31;

            } else if (month == 3) {

                if (year % 4 == 0) {

                    daynum = 29;

                } else {

                    daynum = 28;

                }

            }

            day = daynum + day;

            return day;

        }

        // 获取某一天的月份

        function mygetmonth(month) {

            var year = new Date().getFullYear();

            if (month == 1) {

                month = 12;

                year = year - 1;

            } else {

                month = month - 1;

            }

            return year + "," + month;

        }

        function FormatDate(d) {

            if (d.toString().length == 1) {

                d = "0" + d;

            }

            return d;

        }

//测试填充文本框

        $(function () {

            $('#birthday').datetimebox('setValue', getLastDate());

        });



    </script>