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Editorial Team
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Asked: 2026-06-08T05:05:15+00:00

The Facebook Graph API code I am using to login users is calling my

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The Facebook Graph API code I am using to login users is calling my getfriends() loop function twice. How can I change the code so that the loop function is only called once, whilst still allowing users in various states to login?

    <html xmlns:fb="https://www.facebook.com/2008/fbml">
<head> 
<title>FB App</title> 
<script> 
var userList = [];
    userCount = 0;

function getfriends () {
    console.log("getFriends");
    var url = "/me/friends";
    FB.api(url, function (response) {
        userList = userList.concat(response.data);
        userCount = response.data.length;
        compareAllFriends();
    });
}

function compareAllFriends () {
    console.log("compareAllFriends");
    var i = 0, l = 10, userID;
    for (; i < l; i += 1) {
        userID = userList[i].id;
        compareFriendsWith (i, userID);
    }
}
function compareFriendsWith (i, id) {
    console.log("compareFriendsWith", i, id);
}

</script> 
</head> 
<body>
<div id="fb-root"></div>
<p align="right"><button id="fb-auth">Login</button></p>
<script type="text/javascript">// <![CDATA[
window.fbAsyncInit = function() {
  FB.init({ appId: 'APP_ID', 
        status: true, 
        cookie: true,
        xfbml: true,
        oauth: true});

  function updateButton(response) {
    var button = document.getElementById('fb-auth');

    if (response.authResponse) {
      //user is already logged in and connected
      FB.api('/me', function(response) {
        getfriends();
        button.innerHTML = 'Logout';
      });
      button.onclick = function() {
        FB.logout();
      };
    } else {
      //user is not connected to your app or logged out
      button.innerHTML = 'Login with Facebook';
      button.onclick = function() {
        FB.login(function(response) {
      if (response.authResponse) {
            FB.api('/me');
          } else {
            //user cancelled login or did not grant authorization
          }
        }, {scope:''});     
      }
    }
  }

  // run once with current status and whenever the status changes
  FB.getLoginStatus(updateButton);
  FB.Event.subscribe('auth.statusChange', updateButton);    
};

(function() {
  var e = document.createElement('script'); e.async = true;
  e.src = document.location.protocol 
    + '//connect.facebook.net/en_US/all.js';
  document.getElementById('fb-root').appendChild(e);
}());
// ]]></script>
</body> 
</html>
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1 Answer

  1. Editorial Team

    It appears that the problem may be that updateButton() is run more than once and that in turn calls getfriends() more than once.

    Judging from the Facebook docs, since you set status: true in init(), you don’t need this line:

      FB.getLoginStatus(updateButton);

    That will happen automatically in the next line where you invoke subscribe(). So that’s probably why you’re seeing getfriends() executed twice.

    If that doesn’t work, a quick but much less elegant workaround might be to have a variable like hasfriends, initialize it to false, check its value inside of getfriends(), and have getfriends() do nothing if it’s true. If it’s false, set it to true in getfriends() so the main code in getfriends() only runs once.

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