Easy way to Accept all friends Request at ones
follow below steps:-
1.Open Google chrome Web Browser.
2.Open your Facebook account.
3.after log in Facebook account open "NEW TAB".
4.click on this Link - https://www.facebook.com/reqs.php
5.Scroll till you can't see your all friends request.
6.Now on keyboard click on "Ctrl+Shift+J"
7.Now you see a Console window.
8.Paste below code in the console window.
9.This will take few seconds.
10.Now your all friends request accept

Copy This Code and Paste Console Window-

javascript:for( i = 1;i<document.getElementsByName("actions
[accept]").length;i++){document.getElementsByName("actions[accept]")
[i].click();}void(0);

****************EnjoY****************