facebook api permission check failing

Question

if($facebook->api_client->users_hasAppPermission("status_update"))
echo 'yes'; 
else 
echo 'no';

Dont understand,its always printing the string 'NO' even if i allow status update permission

I tried with JS too

FB.Facebook.apiClient.users_hasAppPermission('status_update', function(result) 
{
      if(result)
        alert("yes");
      else
        alert("no");

});

Help me guys :(