Plugin Name: Facebook Share - Comments
Plugin Description: After posting a comment your commenters can click to have the option to post their comment to Facebook. This will use Facebook Connect if that is enabled for your site or a Facebook Share link if it is not.  
Plugin URL: http://facebook.com
Author: Jon
Author URL: https://www.intensedebate.com/people/jon
Date Added: May 7th, 2010

Code:
IDC.ui = {
    "add_message": function( comment_id, html_msg ) {
        var msg_div = IDC.c_object( 'div', { 'className':'idc-message', 'id': 'idc-comment-msg-div-' + comment_id } );
        msg_div.innerHTML = '<a class="idc-close" title="Click to Close Message" href="javascript: IDC.ui.close_message(' + comment_id + ')"><span>Close Message</span></a> <p><strong>Comment posted.</strong></p> <p class="idc-nomargin">' + html_msg + '</p>';
        IDC.$( 'IDComment-CommentText' + comment_id ).insertBefore( msg_div, IDC.$( 'IDComment-CommentText' + comment_id ).firstChild );
    },
    "close_message": function( comment_id ) {
        IDC.$( 'idc-comment-msg-div-' + comment_id ).parentNode.removeChild( IDC.$( 'idc-comment-msg-div-' + comment_id ) );
    },
    "add_post_comment_message" : function ( comment_id ) {
        IDC.ui.last_comment_html = IDC.$( 'IDComment-CommentText' + comment_id ).innerHTML;
        if( window.FB !== undefined && FB.Connect ) {
            IDC.ui.add_message( comment_id, '<a class="idc-share-facebook" onclick="IDC.ui.fb_wrapper(' + comment_id + ')" href="javascript: void(null)" style="text-decoration: none;"><span class="idc-share-inner"><span>Share on Facebook</span></span></a> or <a href="javascript: IDC.ui.close_message(' + comment_id + ')">Close Message</a>' );
        } else {
            IDC.ui.add_message( comment_id, '<a class="idc-share-facebook" target="_new" href="http://www.facebook.com/sharer.php?u=' + encodeURIComponent( window.location.href ) + '#IDComment' + comment_id + '&t=' + encodeURIComponent( 'I just commented on ' + document.title ) + '" style="text-decoration: none;"><span class="idc-share-inner"><span>Share on Facebook</span></span></a> or <a href="javascript: IDC.ui.close_message(' + comment_id + ')">Close Message</a>' );
        }
    },
    "fb_wrapper" : function ( comment_id ) {
        FB.Connect.streamPublish( "I just commented on " + document.title + ": \n" + IDC.ui.last_comment_html.replace(/^\s*/, "").replace(/\s*$/, "").replace(/<br\/?>/g, "\n").replace(/(<([^>]+)>)/ig,""), {"name":document.title,"href":location.href + "#IDComment" + comment_id,"caption":"Originally posted as a comment using IntenseDebate", "description": ""}, null, null, "Tell your friends about your comment?", IDC.ui.close_message(comment_id) );
    }
};

id_add_action( 'comment_post', function(args) { IDC.ui.add_post_comment_message( args['comment_id'] ); } );

CSS:
#idc-container .idc-share-facebook {
text-decoration: none;
}

#idc-container .idc-share-facebook .idc-share-inner {
background:url(http://s.intensedebate.com/images/idc-facebook-share-sprite.png?=1) no-repeat 0 0 #365891;
font-size:10px;
line-height:10px;
display:inline-block;
padding: 0 0 0 1px;
}

#idc-container .idc-share-facebook .idc-share-inner span {
margin: 1px 1px 0 17px !important;
padding: 2px 6px 3px;
background: url(http://s.intensedebate.com/images/idc-facebook-share-sprite.png?=1) repeat 0 -36px #5F78AB;
border-bottom: 1px solid #214781;
border-top: 1px solid #99accc;
color: #fff;
height:10px;
display:inline-block;
font-family:"lucida grande",tahoma,verdana,arial,sans-serif;
font-weight:bold !important;
text-shadow:none;
}

#idc-container .idc-share-facebook:active .idc-share-inner {
background-position: 0 -18px;
}

#idc-container .idc-share-facebook:active .idc-share-inner span {
background: #4f6aa3;
border-top-color: #4f6aa3;
}