Read here for instructions on confirm/deny buttons:

You may use these buttons on any page, and you can get the styling for
them from userThumbnail.css. You may also use just one button if you
like (i.e. the buttons don't have to come in pairs).

How to use Confirm Request:
To confirm the pending request from the user with user ID 5, use the
following button:
<input onclick="confirmFriendRequest(this)" value="Confirm Request"
id="confirmFriendButtonId-5" />

Note that the ID of the button MUST look like confirmFriendButtonId-X,
where X is the sender's user ID. 

How to use Deny Request:
The same rules apply regarding the button ID, only now it is
denyFriendButtonId-X. A different function is called too:
<input onclick="denyFriendRequest(this)" value="Deny Request"
id="denyFriendButtonId-5" />


The only two rules are that you must give the button the correct ID, and
you must use the correct callback function for onclick. Otherwise,
you're free to customize the buttons as you see fit.

Note: Only one element with a particular ID may exist on a webpage. This
means my implementation has a minor limitation: You may only include one
Confirm or Deny button per user ID on a given page.