How to print a response object comes by facebook login in javascript or jquery?

Facebook response return an object

So for print the response You can use JSON.stringify() function.

You can use this function as mention below

alert(JSON.stringify(response));

Example :
FB.login(function(response) {
                    FB.api('/me', function(response) {
                  var query = FB.Data.query('select src_big from photo where pid in (select cover_pid from album where owner={0} and name="Profile Pictures")', response.id);
                 query.wait(function(rows) {
                         alert(JSON.stringify(response));
                               });
                   });
}