diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..9254b6b
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "polyfill"]
+	path = polyfill
+	url = https://github.com/inexorabletash/polyfill.git
diff --git a/README.md b/README.md
index b685267..e0c5b9d 100644
--- a/README.md
+++ b/README.md
@@ -1,15 +1,9 @@
 jsbasic - Applesoft BASIC in JavaScript
 =======================================
 
-This is hosted for playing with at http://calormen.com/applesoft/ 
+This is hosted for playing with at http://calormen.com/applesoft/
 
-For older browsers, the code depends on various [polyfills](http://github.com/inexorabletash/polyfill).
-For syntax highlighting, the editor optionally uses [CodeMirror](http://codemirror.net) and custom BASIC parser/styles.
-Clone these into sibling directories, so you end up with a structure like:
-
-    jsbasic/
-    polyfill/
-    CodeMirror/
+Use `git clone --recursive` to get [polyfill](http://github.com/inexorabletash/polyfill) for older browsers.
 
 Notes & Known Issues
 --------------------
@@ -35,4 +29,3 @@ You can run your basic programs from the command line (with only basic text inpu
 * Clone the repository locally
 * On Windows, run from a command prompt via: `cscript.exe cbasic.js your_program.txt`
 * On Mac/Linux, install Mozilla Rhino, run from the command prompt via: `java -jar PATH_TO/js.jar cbasic.js your_program.txt`
-
diff --git a/index.htm b/index.htm
index d1cb702..3965d45 100644
--- a/index.htm
+++ b/index.htm
@@ -6,16 +6,16 @@
 <link rel="stylesheet" href="styles.css" type="text/css">
 <meta http-equiv="X-UA-Compatible" content="IE=edge"> <!-- Suppress browser compat button -->
 
-<script type="text/javascript" src="../polyfill/polyfill.js?update=2012-02-08"></script>
-<script type="text/javascript">
+<script src="polyfill/polyfill.js?update=2012-02-08"></script>
+<script>
 (function () {
-  function load(url) { document.write('<script type="text/javascript" src="' + url + '"></' + 'script>'); }
-  if (!window.JSON) { load('../polyfill/json2.js'); }
-  if (!window.localStorage || !window.sessionStorage) { load('../polyfill/storage.js'); }
-  if (!('getContext' in document.createElement('canvas'))) { load('../polyfill/flashcanvas.js'); }
+  function load(url) { document.write('<script src="' + url + '"></' + 'script>'); }
+  if (!window.JSON) { load('polyfill/json2.js'); }
+  if (!window.localStorage || !window.sessionStorage) { load('polyfill/storage.js'); }
+  if (!('getContext' in document.createElement('canvas'))) { load('polyfill/flashcanvas.js'); }
 }());
 </script>
-<script type="text/javascript" src="../polyfill/keyboard.js"></script>
+<script src="polyfill/keyboard.js"></script>
 
 <h1>Applesoft BASIC in Javascript</h1>
 <p>
@@ -130,8 +130,8 @@ By <a href="mailto:inexorabletash@gmail.com">Joshua Bell</a>
 <div id="paper"></div>
 
 <!-- CodeMirror syntax highlighting - this is optional -->
-<script src="../CodeMirror/lib/codemirror.js"></script>
-<link rel="stylesheet" href="../CodeMirror/lib/codemirror.css">
+<script src="//cdnjs.cloudflare.com/ajax/libs/codemirror/3.20.0/codemirror.js"></script>
+<link rel="stylesheet" href="//cdnjs.cloudflare.com/ajax/libs/codemirror/3.20.0/codemirror.css">
 <script src="cm/basic.js"></script>
 <link rel="stylesheet" href="cm/basic.css">
 <style type="text/css">
@@ -139,17 +139,17 @@ By <a href="mailto:inexorabletash@gmail.com">Joshua Bell</a>
 .CodeMirror-scroll { height: 100%; }
 </style>
 
-<script type="text/javascript" src="basic.js?2012-02-08"></script>
-<script type="text/javascript" src="bell.js"></script>
-<script type="text/javascript" src="tty.js"></script>
-<script type="text/javascript" src="lores.js"></script>
-<script type="text/javascript" src="hires.js"></script>
-<script type="text/javascript" src="dos.js"></script>
-<script type="text/javascript" src="printer.js"></script>
-<script type="text/javascript" src="index.js"></script>
+<script src="basic.js?2012-02-08"></script>
+<script src="bell.js"></script>
+<script src="tty.js"></script>
+<script src="lores.js"></script>
+<script src="hires.js"></script>
+<script src="dos.js"></script>
+<script src="printer.js"></script>
+<script src="index.js"></script>
 
 <!-- Google Analytics -->
-<script type="text/javascript">
+<script>
   var _gaq = _gaq || [];
   _gaq.push(['_setAccount', 'UA-18610679-3']);
   _gaq.push(['_trackPageview']);
diff --git a/polyfill b/polyfill
new file mode 160000
index 0000000..fc2ff48
--- /dev/null
+++ b/polyfill
@@ -0,0 +1 @@
+Subproject commit fc2ff48f6ebed7e80c7b3cd62f83e2f22fd3b9bb
diff --git a/reference.htm b/reference.htm
index 9b9ffb2..5854d88 100644
--- a/reference.htm
+++ b/reference.htm
@@ -594,7 +594,7 @@ function which implements the logic for walking over the array.<p>
 </ol>
 </section>
 
-<script type="text/javascript" src="../polyfill/polyfill.js"></script>
+<script src="polyfill/polyfill.js"></script>
 <script>
 (function buildTOC(el) {
   var html = [];
diff --git a/script.js b/script.js
index f511c87..427b80c 100644
--- a/script.js
+++ b/script.js
@@ -7,15 +7,15 @@
 
   document.write('<link rel="stylesheet" href="' + baseURL + 'display.css">');
 
-  function load(url) { document.write('<script type="text/javascript" src="' + url + '"></script>'); }
-  load(baseURL + '../polyfill/polyfill.js');
-  load(baseURL + '../polyfill/keyboard.js');
-  load(baseURL + 'tty.js');
-  load(baseURL + 'lores.js');
-  load(baseURL + 'hires.js');
-  load(baseURL + 'bell.js');
-  load(baseURL + 'dos.js');
-  load(baseURL + 'basic.js');
+  function load(url) { document.write('<script src="' + baseURL + url + '"></script>'); }
+  load('polyfill/polyfill.js');
+  load('polyfill/keyboard.js');
+  load('tty.js');
+  load('lores.js');
+  load('hires.js');
+  load('bell.js');
+  load('dos.js');
+  load('basic.js');
 
   function createInstance(src) {
     function ce(element, attributes, children) {