Facebook web SDK - identify user has clicked close button on facebook login popup

I am using facebook web SDK in my application for single signon. Consider following scenario - - user logs in to facebook - User launches our application. Clicks on login using facebook button (custom button). On click of button calling method FB.login(.........) - popup for facebook login is displayed (popup by facebook SDK). As user is already into facebook in other tab, login popup prompts for password. - User clicks on close button (top bar x button). - Though user has clicked on X button, FB.login call returns success with response.status as "connected"

my Issue is i want to identify user has clicked on cancel button, so that custom action can be taken. Basically i would like to identify user has clicked on close/cancel button. thanks in advance.