Question

how can i this code to get user id in another functions and use as global variable??

    function get_id() {
        FB.getLoginStatus(function(response) {
      if (response.status === 'connected') {
        // the user is logged in and connected to your
        // app, and response.authResponse supplies
        // the user’s ID, a valid access token, a signed
        // request, and the time the access token 
        // and signed request each expire
        uid = response.authResponse.userID;
        accessToken = response.authResponse.accessToken;
      } else if (response.status === 'not_authorized') {
        // the user is logged in to Facebook, 
        //but not connected to the app
      } else {
        // the user isn't even logged in to Facebook.
      }
    });
    }

fb_user_id = get_id();

Answer 1

Your best bet would be to set this variable inside the function instead of assignment through calling:

(function(w) {
    FB.getLoginStatus(function(response) {
        if (response.status === 'connected') {
            // the user is logged in and connected to your
            // app, and response.authResponse supplies
            // the user’s ID, a valid access token, a signed
            // request, and the time the access token 
            // and signed request each expire

            w.fb_user_id = response.authResponse.userID;
            w.accessToken = response.authResponse.accessToken;
        } else if (response.status === 'not_authorized') {
            // the user is logged in to Facebook, 
            //but not connected to the app
        } else {
            // the user isn't even logged in to Facebook.
        }
    });
})(window);

Then later on in your page (provided the call is not dependent on this one immediately), you can access your variable anywhere on the page as the global variable fb_user_id (also known as window.fb_user_id.

If you need to run code as soon as the user ID is ready, you will need to use a callback. If you are using jQuery 1.5 you can also use jQuery Deferreds to help with the synchronicity issues:

var getUserId = function () {
    return $.Deferred(function(d) {
        FB.getLoginStatus(function(response) {
            if (response.status === 'connected') {
                // the user is logged in and connected to your
                // app, and response.authResponse supplies
                // the user’s ID, a valid access token, a signed
                // request, and the time the access token 
                // and signed request each expire
                var auth = response.authResponse;
                d.resolve(auth.userID, auth.accessToken);
            } else if (response.status === 'not_authorized') {
                // the user is logged in to Facebook, 
                //but not connected to the app

                d.reject();
            } else {
                // the user isn't even logged in to Facebook.

                d.reject();
            }
        });

    }).promise();   
};

getUserId()
    .done(function(userId, token) {
        // userId and token are available in here
    })
    .fail(function() {
        // run some code in here if not authorized
        // or something else failed;
    });