http://www.facebook.com/sharer/sharer.php?u=http%3A%2F%2Fwww.google.com
How can I customize the text and image. It looks like Facebook pulled the docs.
You can use the Feed Dialog via URL to emulate the behavior of Sharer.php, but it's a little more complicated. You need a Facebook App setup with the Base URL of the URL you plan to share configured. Then you can do the following:
1) Create a link like:
http://www.facebook.com/dialog/feed?app_id=[FACEBOOK_APP_ID]' +
'&link=[FULLY_QUALIFIED_LINK_TO_SHARE_CONTENT]' +
'&picture=[LINK_TO_IMAGE]' +
'&name=' + encodeURIComponent('[CONTENT_TITLE]') +
'&caption=' + encodeURIComponent('[CONTENT_CAPTION]) +
'&description=' + encodeURIComponent('[CONTENT_DESCRIPTION]') +
'&redirect_uri=' + FBVars.baseURL + '[URL_TO_REDIRECT_TO_AFTER_SHARE]' +
'&display=popup';
(obviously replace the [CONTENT] with the appropriate content. Documentation here: https://developers.facebook.com/docs/reference/dialogs/feed)
2) Open that link in a popup window with JavaScript on click of the share link
3) I like to create file (i.e. popupclose.html) to redirect users back to when they finish sharing, this file will contain to close the popup window
The only downside of using the Feed Dialog (besides setup) is that, if you manage Pages as well, you don't have the ability to choose to share via a Page, only a regular user account can share. And it can give you some really cryptic error messages, most of them are related to the setup of your Facebook app or problems with either the content or URL you are sharing.