diff --git a/lib/ace/lib/dom.js b/lib/ace/lib/dom.js
index 81c9773a..4df72736 100644
--- a/lib/ace/lib/dom.js
+++ b/lib/ace/lib/dom.js
@@ -33,6 +33,12 @@ define(function(require, exports, module) {
 
 var XHTML_NS = "http://www.w3.org/1999/xhtml";
 
+exports.getDocumentHead = function(doc) {
+    if (!doc)
+        doc = document;
+    return doc.head || doc.getElementsByTagName("head")[0] || doc.documentElement;
+}
+
 exports.createElement = function(tag, ns) {
     return document.createElementNS ?
            document.createElementNS(ns || XHTML_NS, tag) :
@@ -134,8 +140,7 @@ exports.importCssString = function importCssString(cssText, id, doc) {
         if (id)
             style.id = id;
 
-        var head = doc.head || doc.getElementsByTagName("head")[0] || doc.documentElement;
-        head.appendChild(style);
+        exports.getDocumentHead(doc).appendChild(style);
     }
 };
 
@@ -147,8 +152,7 @@ exports.importCssStylsheet = function(uri, doc) {
         link.rel = 'stylesheet';
         link.href = uri;
 
-        var head = doc.head || doc.getElementsByTagName("head")[0] || doc.documentElement;
-        head.appendChild(link);
+        exports.getDocumentHead(doc).appendChild(link);
     }
 };
 
diff --git a/lib/ace/lib/net.js b/lib/ace/lib/net.js
index e125582e..3869da45 100644
--- a/lib/ace/lib/net.js
+++ b/lib/ace/lib/net.js
@@ -7,6 +7,7 @@
  */
 define(function(require, exports, module) {
 "use strict";
+var dom = require("./dom");
 
 exports.get = function (url, callback) {
     var xhr = new XMLHttpRequest();
@@ -22,18 +23,19 @@ exports.get = function (url, callback) {
 };
 
 exports.loadScript = function(path, callback) {
-    var head = document.head || document.getElementsByTagName('head')[0];
+    var head = dom.getDocumentHead();
     var s = document.createElement('script');
 
     s.src = path;
     head.appendChild(s);
 
-    if (s.onload !== undefined)
-        s.onload = callback;
-    else
-        s.onreadystatechange = function () {
-            this.readyState == 'loaded' && callback();
-        };
+    s.onload = s.onreadystatechange = function(_, isAbort) {
+        if (isAbort || !s.readyState || s.readyState == "loaded" || s.readyState == "complete") {
+            s = s.onload = s.onreadystatechange = null;
+            if (!isAbort)
+                callback();
+        }
+    };
 };
 
 });