Question: I have developed one SharePoint site for Performance Review.

Site has custom html page with jQuery that creates/updates record using REST and that page is blinded using ASPX page. (I will explain the functionalities used in this page at end of this question)

I have given edit permission to all end users so that they can create/update record in performance review list using ASPX page. (validation on custom page are handled manually).

for hiding the performance review list data from end users I have given audience targeting on all items view of the performance list

I feel that I can develop something better, secured then what I have developed, I need your suggestions to know how can i build this better.

I have SharePoint 2013 and SharePoint Online, please suggest for both.

**About custom HTML Page**

It has sections as below,

* Section 1 Employee Comments
* Section 1 Employee self rating
* Section 1 Manger comments
* Section 1 manager rating

such 4 sections are there.
when employee opens the form, manger columns are hided using jQuery.
when manager opens the form, manger columns are shown and employee columns are turned read only using jQuery.

**How I identified when to open same form as employee and manager**

When employee fills the form and submits (when record is created), the designer workflow sends as email to manger containing link with one parameter(employee\_unique\_id).
jQuery will check that the parameter is passed so it will open manager related columns for manger to fill up.

Answer: 
An "Office 365 Group" is a (special) Active Directory group **plus** a Site Collection. This AD group can be used as an ordinary AD group when granting access to other sites. When used this way, they are just an AD group with no special "Office 365 Group" features in that site. I.e. they are managed as ordinary SharePoint users and are directly assigned permissions to a item, or are added to a "classic" SharePoint group. They will not be treated in any special way because they were an "owner" or "member" in the "Office 365 Group".
You can only connect an Office 365 group to an existing SharePoint site. It is a one-to-one relationship.