Coffeescript version of the JS from this answers on stackoverflow: http://stackoverflow.com/a/2174733/76486 It helps you use jquery in an embedded widget without conflicting with other javascript on the page

gistfile1.coffee

main = (window, document, version, callback) ->
  [j, d, loaded] = [null, null, false]
  if !(j = window.jQuery) || version > j.fn.jquery || callback(j, loaded)
    script = document.createElement("script");
    script.type = "text/javascript";
    script.src = "//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js";
    script.onload = script.onreadystatechange = () ->
      if !loaded && (!(d = this.readyState) || d == "loaded" || d == "complete")
        callback((j = window.jQuery).noConflict(1), loaded = true)
        j(script).remove();
    document.documentElement.childNodes[0].appendChild(script)

main window, document, "1.7", ($, jquery_loaded) ->
  # Widget code here

I can't edit it now (wasn't signed in when creating it) but I ended up changing

document.documentElement.childNodes[0].appendChild(script)

to

(document.getElementsByTagName("head")[0] || document.documentElement).appendChild(script_tag)

Because it was throwing errors when inserting into badly formed html (blank line at top of file).