How can I find out if a user has clicked the Facebook Like button on my website?

I want to include content on my website which will only be displayed if the user has clicked the Facebook Like button on the very same page. I see in the documentation there is the "edge.create" event which I can subscribe to but won't that only fire when the user likes the page the very first time? If a user has already liked the page, I want him to be able to come back and download again without having to unlike and then like again.

I also notice that this information can be queried through FQL and 开发者_StackOverflow中文版the likes but it's not clear what the auth requirements are for this.

Is it possible to do this in some way without extra authentication? I want there to only be a single step for the user if he is already logged in.

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Check out these two links to see if they can help you:

This one covers the edge.create: Display content after clicking Facebook Like button

This one covers if a person has already "liked" a page: How to check if a user likes my Facebook Page or URL using Facebook's API