日期控件控制两个日期相差7天

var dates1 = $( "#stime, #etime" ).datetimepicker({
        dateFormat: 'yy-mm-dd', 
        timeFormat:'HH:mm:ss',
        //minDate: -7, 
        maxDate: +0,
        showTime: true,
        onSelect: function( selectedDate ) {
            var option = this.id == "stime" ? "maxDate" : "minDate",
                instance = $( this ).data( "datepicker" ),
                date = $.datepicker.parseDate(
                    instance.settings.dateFormat ||
                    $.datepicker._defaults.dateFormat,
                    selectedDate, instance.settings );
            
            var curdate = date.getDate();
            // 控制日期之间相隔天数，1为一天
            curdate = this.id == "etime" ? curdate - 7 : curdate + 7;
            var cur_date=new Date().getDate();
            
            if(cur_date>=curdate - 7){
                curdate=cur_date;
            }
            date.setDate(curdate);
            
            
            dates1.not( this ).datetimepicker( "option", option, date );
            
            if(option=='maxDate'){
                dates1.not( this ).datetimepicker( "option", "minDate", $(this).val() );
            }else{
                dates1.not( this ).datetimepicker( "option", "maxDate", $(this).val() );
            }
            
        }
    });