Greasemonkey/Javascript Help

[DrWho1988]

Hi I've been trying to learn JS by messing around with Greasemonkey, tweaking peoples scripts and whatnot. Anyways I'm trying to add a "Like" button from Facebook to the first post of a thread. Yes I know there's the "Share This Thread!" link but like I said I'm using this merely as a self learning tool.
I think I have the code correct, but apparently not since it doesn't work.

Maybe someone here can help me out

// ==UserScript==
// @name          MMOwned Like
// @namespace     Dr. Watson
// @description   Like a topic on MMOwned!
// @include       http://www.mmowned.com/forums/*
// ==/UserScript==

base_url = getBaseURL();

var base_url = getBaseURL(window.location);

//HTML/CSS added to page
var like_html = '';
like_html = '<div style="float: left;"><iframe src="http://www.facebook.com/plugins/like.php?href=' + window.location + '&layout=box_count&show_faces=true&width=450&action=like&font=segoe+ui&colorscheme=dark&height=65" scrolling="no" frameborder="0" style="border:none; overflow:hidden; width:450px; height:65px;" allowTransparency="true"></iframe></div>';

output = document.createElement('div');
output.innerHTML = like_html;

//add HTML to id posthead
var op = document.getElementById('posthead');
    op = op.getElementByTagName('a');
    op = op.getElementByName('1');
if (op) {
        op.parentNode.insertBefore(output, op.nextSibling);
    }

//get url of thread 
function getBaseURL () {
  var url = location.href;
  var baseURL = url.substring(0, url.indexOf('/', 14));
  
  if (baseURL.indexOf('http://localhost') != -1) {
    var url = location.href;
    var pathname = location.pathname;
    var index1 = url.indexOf(pathname);
    var index2 = url.indexOf("/", index1 + 1);
    var baseLocalUrl = url.substr(0, index2);

    return baseLocalUrl + "/";
  }
  else {
    return baseURL + "/";
  }
}

[2dgreengiant]

Did you check out the developer page on facebook? It has some references etc u can use i think

[DrWho1988]

Did you check out the developer page on facebook? It has some references etc u can use i think

Yeah that's where I got the iframe code from. The problem I'm having is that it's either not loading the script at all or its just not inserting the code in the header of the first post. I'm not sure how to debug stuff like this yet