How to get Facebook message content from Send button?

We have a Facebook send button开发者_开发百科 that we'd like to capture the actual message that is sent. We are using the FB API to capture the message.send callback event, but it doesn't seem to have the actual message content in it.

Anyone know how to get this message content?

There is no way to retrieve this information directly from the send button since the user has not explicit granted you access to that information. You can retrieve the message having the user grant you the read_inbox permission, which provides the ability to read from a user's Facebook Inbox.