Question: It seems that when creating a Send button, Facebook will not let me send a link to the current iFrame tab / app. The link always gets reduced to just the Facebook page.

For example, I want to create a Send button using the following href:
<http://www.facebook.com/pages/MyPage/pageid/?sk=app_my_app_id&app_data=My_app_data>

But in the send button, the link gets reduced to:
<http://www.facebook.com/pages/MyPage/pageid>

Any ideas on how to get straight to the correct tab and include the app\_data?

Answer: 
After a bit of browsing, looks like you can't include url params on the facebook send button link. The workaround I've had to use on my project is to encode any parameters as a 'fake' url and rewrite when this when it comes back in to my server:

E.g. instead of this on the FB button link:
<http://example.com/index.php?foo=bar>

Use something like this:
<http://example.com/foo/bar.html>

Then setup some suitable mod\_rewrite rules on your server to redirect incoming links to the 'fake' url, back to your usual url.
Facebook Like, Recommend, and Send buttons will not allow you to link to a tab on a page. I ran into this problem myself, and found a workaround solution.

I used Facebook's share feature to create a share button or share link. When users click the link, they are taken to a page that links directly to the tab. They can select whether to share it on their own Facebook wall or in a private message.

Here's how:

```
<a href="http://www.facebook.com/share.php?u=URL_TO_FACEBOOK_PAGE_TAB" title="Share this with your friends!">Click here to share this with your friends!</a>

```

You can replace "Click here to share this with your friends" with an image if you would like. If you would like the link to open the share feature in a new window or tab, add target="\_blank" to the parameters.

There's always a chance that Facebook might not support this style of share link forever...but this works for the time being.