I\'ve set up a Canvas Page which doe\'s a FB.login on click of a form submit button. During the following request it tries to access the users data via $facebook->api(\'/me\
I had a lot of troubles with the JS FB login stuff. I recommend using the simpler redirect login using oauth and the getLoginUrl function from php fb api.
So basically you do it from PHP, you check if you have your session, if not you use getLoginUrl and redirect to that page, your use will be then redirected to your app/site with a valid session (if he accepts).
Does this help ? I really lost HOURS trying to make the FB JS login work on any browser and I couldn't, I've switched since then to the simple redirect login method in all of my apps with complete success.