Simple example of popup authentication with Facebook Graph API

Why not simply...

function authorizeAppInPopup() {
    FB.login(function(response) {
        if (response.authResponse) {
            // User authorized app
        } else {
            // User cancelled login or did not fully authorize
        }
    }, {scope: 'publish_stream'});
}

??? : ]

https://developers.facebook.com/docs/reference/javascript/FB.login/

oauth2 in facebook involves two steps, call authorize to get code, then call access_token to get token. One way to deal with the pop login:

open login url in new window just like you did,when the facebook redirects back to your url in the popup, you set the cookie either through server side code or using javascript to capture url query parameter, when page is loaded in the popup, close the window immediately window.close.

On your main page, after your window.open code, add JavaScript code to detect if popup is closed and capture the cookie:

var signinWin;
$('#FacebookBtn').click(function () {
        var pos = screenCenterPos(800, 500);
        signinWin = window.open("[URL]", "SignIn", "width=780,height=410,toolbar=0,scrollbars=0,status=0,resizable=0,location=0,menuBar=0,left=" + pos.x + ",top=" + pos.y);
        setTimeout(CheckLoginStatus, 2000);
        signinWin.focus();
        return false;
    });

function CheckLoginStatus() {
    if (signinWin.closed) {
        $('#UserInfo').text($.cookie("some_cookie"));
    }
    else setTimeout(CheckLoginStatus, 1000);
}