Facebook has a tool that generates short-lived access tokens for all your apps, but it's not as easy as you might think to get a long-lived token manually. This bookmarklet bridges that gap.

1. Visit the Bookmarklet Installation Page and drag the link there to the Bookmarks bar in your browser.
2. Have your Facebook App ID and App Secret handy.
3. Login to the Facebook Access Token Tool in your browser to see short-lived tokens for all your apps.
4. Select/highlight the short-lived token you want to convert into a long-lived token. (Double-clicking on the token should select it.)
5. Click the bookmarklet and specify these values (which you should have handy) in the two prompts:
   1. App ID
   2. App Secret
6. The browser will load a Facebook response with the long-lived token included in it. It will be the long string after the access_token= and before the &expires.