function DateAdd(interval, number, date) {
            /*
            *   功能:实现JSScript的DateAdd功能.
            *   参数:interval,字符串表达式，表示要添加的时间间隔.
            *   参数:number,数值表达式，表示要添加的时间间隔的个数.
            *   参数:date,时间对象.
            *   返回:新的时间对象.
            *   var   now   =   new   Date();
            *   var   newDate   =   DateAdd( "d ",5,now);
            *---------------   DateAdd(interval,number,date)   -----------------
            */
            switch (interval) {
                case "y ":
                    {
                        date.setFullYear(date.getFullYear() + number);
                        return date;
                        break;
                    }
                case "q ":
                    {
                        date.setMonth(date.getMonth() + number * 3);
                        return date;
                        break;
                    }
                case "m ":
                    {
                        date.setMonth(date.getMonth() + number);
                        return date;
                        break;
                    }
                case "w ":
                    {
                        date.setDate(date.getDate() + number * 7);
                        return date;
                        break;
                    }
                case "d ":
                    {
                        date.setDate(date.getDate() + number);
                        return date;
                        break;
                    }
                case "h ":
                    {
                        date.setHours(date.getHours() + number);
                        return date;
                        break;
                    }
                case "m ":
                    {
                        date.setMinutes(date.getMinutes() + number);
                        return date;
                        break;
                    }
                case "s ":
                    {
                        date.setSeconds(date.getSeconds() + number);
                        return date;
                        break;
                    }
                default:
                    {
                        date.setDate(d.getDate() + number);
                        return date;
                        break;
                    }
            }
        }
    //调用
       var newDate = DateAdd("y ", 1, dtADate);