When I tried the application clicking on the G+ button nothing happened. I turned on Firebug and I get this error message
TypeError: can't convert authResult[field] to primitive type
$('#authResult').append(' ' + field + ': ' + authResult[field] + '<br/>');
localhost:4567 (line 87)
For me the solution was to eliminate the output of the 'status' variable:
index.html lines 87-89
if (field != 'status') {
$('#authResult').append(' ' + field + ': ' + authResult[field] + '<br/>');
}