How to get access token from FB.login method in javascript SDK

response.session.access_token doesn't work in my code. But this works: response.authResponse.accessToken

     FB.login(function(response) { alert(response.authResponse.accessToken);
     }, {perms:'read_stream,publish_stream,offline_access'});

You can get access token using FB.getAuthResponse()['accessToken']:

FB.login(function(response) {
   if (response.authResponse) {
     var access_token =   FB.getAuthResponse()['accessToken'];
     console.log('Access Token = '+ access_token);
     FB.api('/me', function(response) {
     console.log('Good to see you, ' + response.name + '.');
     });
   } else {
     console.log('User cancelled login or did not fully authorize.');
   }
 }, {scope: ''});

Edit: Updated to use Oauth 2.0, required since December 2011. Now uses FB.getAuthResponse(); If you are using a browser that does not have a console, (I'm talking to you, Internet Explorer) be sure to comment out the console.log lines or use a log-failsafe script such as:

if (typeof(console) == "undefined") { console = {}; } 
if (typeof(console.log) == "undefined") { console.log = function() { return 0; } }