store record 集合转换为字符数组传到后台的方法

 var recs = store.getRange();
            var dt = store.getModifiedDataStringArr(recs) || [];
            $.ajaxExec("update", { JsonString: AimFrm.getJsonString(), data: dt }, function(rtn) {
                if (rtn.data.ID) {
                    alert("保存成功！");
                    if (window.opener && window.opener.store) {
                        window.opener.store.reload();
                    }
                    window.close();
                }
            })