JS: Facebook Login button changes states if I login to facebook.com in another tab

问题

My Facebook Login button is showing as Logged Out on my site. If I open a new tab in the browser, go to www.facebook.com and sign in successfully, then go back to the my website's tab and refresh the page, the facebook login button now shows as Logged In. Is that the expected behavior here? Seems strange since I never 'clicked' to log in with facebook on my site.

function statusChangeCallback(response) {

  if (response && response.authResponse && response.authResponse.accessToken) {

     Cookies.set("facebookToken",response.authResponse.accessToken, { expires: 7 })
  }

  if (response.status === 'connected') {
    Cookies.set("showFacebookProceed", true)
  } else {
    let element = document.getElementById('fb-proceed');
    element.remove()
    Cookies.remove("showFacebookProceed")

  }
}


checkLoginState = function() {
  FB.getLoginStatus(function(response) {
    statusChangeCallback(response);
  });
};


window.fbAsyncInit = function() {
  FB.init({
    appId      : 'REDACTED', 
    cookie     : true,  
    status     : true,                  
    xfbml      : true,  // parse social plugins on this page
    version    : 'v2.8' // use graph api version 2.8
  });
  FB.getLoginStatus(function(response) {
       statusChangeCallback(response);
  });


   FB.Event.subscribe('auth.authResponseChange', function(response) {
        statusChangeCallback(response);
  });



};

// async load of SDK 
(function(d, s, id) {
  var js, fjs = d.getElementsByTagName(s)[0];
  if (d.getElementById(id)) return;
  js = d.createElement(s); js.id = id;
  js.src = "https://connect.facebook.net/en_US/sdk.js";
  fjs.parentNode.insertBefore(js, fjs);
  }(document, 'script', 'facebook-jssdk'));

}

My HTML Button is:

 <div 
   class="fb-login-button"
   data-max-rows="1"
   data-width="314"
   data-auto-logout-link="true"
   data-scope="email"
   data-use-continue-as="true"
   data-button-type="login_with"
 /></div>

回答1:

Yes. This is the expected behavior.

Facebook sdk uses the currently logged in user in your browser. If not logged in, it will ask you to login otherwise no.

You can try the reverse of what you did and test:

Logout of Facebook from browser
Login using Login button in your site

Now if you visit Facebook website you will be logged in as that user even though you logged in from your website. So in both case the same thing is happening.

来源：https://stackoverflow.com/questions/54244589/js-facebook-login-button-changes-states-if-i-login-to-facebook-com-in-another-t

标签

javascript

facebook

facebook-javascript-sdk