To load a script file with great cross-browser support

load-script-file-cross-browser

loadScript = (src, callback) ->
    script = document.createElement("script")
    loaded = undefined
    script.setAttribute "type", "text/javascript"
    script.setAttribute "src", src
    if script.readyState
      script.onreadystatechange = -> # For old versions of IE
        callback()  if @readyState is "complete" or @readyState is "loaded"
        return
    else # Other browsers
      script.onload = callback
    (document.getElementsByTagName("head")[0] or document.documentElement).appendChild script