If you are working in facebook application, you may need to ask your user for extended permission. If you want to know more about extended permission please visit here and learn about extended permission.
In short, if your application want to access some special info of user or want to do some special tasks then it need the permission of the user. Now I’m describing how will you prompt for extended permission.
There is an FBML tag for this purpose
<fb:prompt-permission perms="read_stream,publish_stream">Would you like our application to read from and post to your News Feed?</fb:prompt-permission>
This code will render a link, when user will click that link, a permission box will open and ask user to give extended permission. But if that user already given that permission, then the box will open and close.
The special permission box looks like this:
The answer is its also possible as facebook provided a function for it.
Facebook.showPermissionDialog('publish_stream, read_stream', ondone, showProfileSelector, '');
So for fbml reference visit: http://wiki.developers.facebook.com/index.php/Fb:prompt-permission
for fbjs reference visit: http://wiki.developers.facebook.com/index.php/Facebook.showPermissionDialog