From 797f9f832a10a99a3364e45216792bce41c8bcba Mon Sep 17 00:00:00 2001
From: Juan Manuel Gimeno Illa <jmgimeno@gmail.com>
Date: Wed, 9 May 2018 17:09:59 +0200
Subject: [PATCH] RankNTypes (9 May 2018)

---
 rankntypes/rankntypes.html  |   63 +-
 rankntypes/rankntypes.lhs   |   63 +-
 rankntypes/scripts/slidy.js | 3078 +++++++++++++++++++++++++++++++++++
 rankntypes/styles/slidy.css |  403 +++++
 4 files changed, 3544 insertions(+), 63 deletions(-)
 create mode 100644 rankntypes/scripts/slidy.js
 create mode 100644 rankntypes/styles/slidy.css

diff --git a/rankntypes/rankntypes.html b/rankntypes/rankntypes.html
index 1b10f69..7de6f6a 100644
--- a/rankntypes/rankntypes.html
+++ b/rankntypes/rankntypes.html
@@ -6,7 +6,7 @@
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
   <meta http-equiv="Content-Style-Type" content="text/css" />
   <meta name="generator" content="pandoc" />
-  <meta name="author" content="Juan Manuel Gimeno" />
+  <meta name="author" content="Juan Manuel Gimeno Illa" />
   <title>RankNTypes (second step in the path to lenses)</title>
   <style type="text/css">code{white-space: pre;}</style>
   <style type="text/css">
@@ -55,9 +55,9 @@
 <div class="slide titlepage">
   <h1 class="title">RankNTypes (second step in the path to lenses)</h1>
   <p class="author">
-Juan Manuel Gimeno
+Juan Manuel Gimeno Illa
   </p>
-  <p class="date">2 May 2018</p>
+  <p class="date">9 May 2018</p>
 </div>
 <div id="index" class="slide section level1">
 <h1>Index</h1>
@@ -71,13 +71,16 @@ <h1>Index</h1>
 <div id="language-extensions" class="slide section level1">
 <h1>Language extensions</h1>
 <ul>
-<li><p>Haskell is a <strong>well defined</strong> Language</p>
+<li><p>Haskell is defined (althought not formally) in</p>
 <ul>
 <li><a href="https://www.haskell.org/onlinereport/">Haskell '98 Report</a></li>
 <li><a href="https://www.haskell.org/onlinereport/haskell2010/">Haskell 2010 Report</a></li>
 </ul></li>
 <li><p>But Haskell was meant to be a playground for experimenting with new functional constructs</p></li>
-<li><p>So GHC embraced the notion of extensions: opt-in functionality that gives the user even more tools when writing their programs</p></li>
+<li><p>So GHC embraced the notion of extensions:</p>
+<ul>
+<li>opt-in functionality that gives the user even more tools when writing their programs</li>
+</ul></li>
 <li><p>The extension that we'll need to use for representing lenses is one that allows <strong>higher rank polymorphism</strong>:</p></li>
 </ul>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">{-# LANGUAGE RankNTypes #-}</span></code></pre></div>
@@ -94,14 +97,14 @@ <h1>Monomorphism</h1>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">intId ::</span> <span class="dt">Integer</span> <span class="ot">-&gt;</span> <span class="dt">Integer</span>
 intId x <span class="fu">=</span> x</code></pre></div>
 <ul>
-<li><code>intId</code> is a fully defined value (a function) od a fully defined type <code>Integer -&gt; Integer</code></li>
+<li><code>intId</code> is a fully defined value (a function) of a fully defined type <code>Integer -&gt; Integer</code></li>
 </ul>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">doubleId ::</span> <span class="dt">Double</span> <span class="ot">-&gt;</span> <span class="dt">Double</span>
 doubleId x <span class="fu">=</span> x</code></pre></div>
 <ul>
-<li><p>This is a complete different value of a completely different types</p>
+<li><p>This is a complete different value of a completely different type</p>
 <ul>
-<li>But their definitions are exactly the same?</li>
+<li><strong>But their definitions are exactly the same !!????</strong></li>
 </ul></li>
 </ul>
 </div>
@@ -113,15 +116,14 @@ <h1>Polymorphism</h1>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell">id<span class="ot"> ::</span> a <span class="ot">-&gt;</span> a
 id x <span class="fu">=</span> x</code></pre></div>
 <ul>
-<li><p>The definition is still the same</p></li>
 <li><p>This kind of polymorphism is called <strong>parametric polimorphism</strong> (in other languages known as <em>generics</em>)</p></li>
-<li><p><strong>Haskell will only allow this if there is indeed a single definition</strong></p>
+<li><p>Haskell will only allow this if there is indeed a <strong>single definition</strong></p>
 <ul>
 <li>You cannot choose the defintion based on its type</li>
 </ul></li>
 <li><p>It also adds safety through a property called <strong>parametricity</strong>:</p>
 <ul>
-<li><p>If we pretend there are no loops or exceptions, then the function <strong>fully determined</strong> by its type.</p></li>
+<li><p>If we pretend there are no loops or exceptions, then the <code>id</code> function is <strong>fully determined</strong> by its type.</p></li>
 <li><p>So, if we see the type <code>a -&gt; a</code> it must be the identity function !!!</p></li>
 </ul></li>
 </ul>
@@ -129,10 +131,9 @@ <h1>Polymorphism</h1>
 <div id="rank-1-polymorphism" class="slide section level1">
 <h1>Rank-1 polymorphism</h1>
 <ul>
-<li><p>Usuelly the cal <code>id</code> <strong>the identity function</strong> but in fact we should think of it as a <strong>whole family of functions</strong></p>
+<li><p>Usually we calll <code>id</code> <strong>the identity function</strong> but in fact we should think of it as a <strong>whole family of functions</strong></p>
 <ul>
-<li><p>we should really say there is a function <strong>for all</strong> types a</p></li>
-<li><p>that is, for every type <code>a</code>, there is and identity function called <code>id</code>, which is of type <code>a -&gt; a</code></p></li>
+<li>that is, <strong>for all</strong> type <code>a</code>, there is and identity function called <code>id</code>, which is of type <code>a -&gt; a</code></li>
 </ul></li>
 <li><p>This is the view of the type-checker and by turning the <code>RankNtypes</code> extension we can be explicit about it</p></li>
 </ul>
@@ -160,18 +161,18 @@ <h1>Rank-1 polymorphism</h1>
 </ul>
 <div class="sourceCode"><pre class="sourceCode haskell"><code class="sourceCode haskell">print (id (<span class="dv">3</span><span class="ot"> ::</span> <span class="dt">Integer</span>), id <span class="st">&quot;blah&quot;</span>)</code></pre></div>
 <ul>
-<li><p>Another way to look at it is in terms of <strong>promise and demand</strong></p>
+<li><p>Another way to look at it is in terms of <strong>promise</strong> and <strong>demand</strong></p>
 <ul>
 <li><p>the <strong>type signature</strong> of <code>id</code> <strong>promises</strong> that the definition works <strong>for all types</strong></p></li>
-<li><p>when you actually <strong>apply</strong> the function you <strong>demand a certain type</strong></p></li>
-<li><p>This interpretation will be very useful when we move to higher-rank polymorphism</p></li>
+<li><p>when you actually <strong>apply</strong> the function to a value, you <strong>demand for a certain type</strong></p></li>
 </ul></li>
+<li><p>This interpretation will be very useful when we move to higher-rank polymorphism</p></li>
 </ul>
 </div>
 <div id="rank-2-and-higher-polymorphism" class="slide section level1">
 <h1>Rank-2 and higher polymorphism</h1>
 <ul>
-<li>Let's us the explicitness of the quantifier in a type alias</li>
+<li>Let's use the explicitness of the quantifier in a type alias</li>
 </ul>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="kw">type</span> <span class="dt">IdFunc</span> <span class="fu">=</span> forall a<span class="fu">.</span> a <span class="ot">-&gt;</span> a</code></pre></div>
 <ul>
@@ -184,28 +185,26 @@ <h1>Rank-2 and higher polymorphism</h1>
 </ul>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">someInt ::</span> <span class="dt">IdFunc</span> <span class="ot">-&gt;</span> <span class="dt">Integer</span></code></pre></div>
 <ul>
-<li><p>Since any value of type <code>IdFunc</code> must be the identity funcion, <code>someInt</code> is a function which expects the identity function as its argument and returns an Integer</p></li>
-<li><p>Let's give it some <em>arbitray</em> definition</p></li>
+<li><p>Since any value of type <code>IdFunc</code> must be the identity function, <code>someInt</code> is a function which expects the identity function as its argument and returns an Integer</p></li>
+<li><p>Let's give it some <em>arbitrary</em> definition</p></li>
 </ul>
 <div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell">someInt id&#39; <span class="fu">=</span> id&#39; <span class="dv">3</span></code></pre></div>
 </div>
 <div id="rank-2-and-higher-polymorphism-1" class="slide section level1">
 <h1>Rank-2 and higher polymorphism</h1>
+<div class="sourceCode"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span class="ot">someInt ::</span> <span class="dt">IdFunc</span> <span class="ot">-&gt;</span> <span class="dt">Integer</span>
+someInt id&#39; <span class="fu">=</span> id&#39; <span class="dv">3</span></code></pre></div>
 <ul>
-<li>Let's give it some <em>arbitrary</em> definition</li>
-</ul>
-<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell">someInt id&#39; <span class="fu">=</span> id&#39; <span class="dv">3</span></code></pre></div>
-<ul>
-<li><p>This is something new that we didn’t have before !!!!</p>
+<li><p>This is <strong>something new</strong> that we didn’t have before !!!!</p>
 <ul>
 <li><code>someInt</code> has received a function <code>id'</code> about which it knows that it is the fully fledged polymorphic identity function</li>
 <li>so <strong>it can instantiate its type variable as it likes</strong>, and it does so.</li>
 </ul></li>
 <li><p>The someInt function isn’t even polymorphic !!!!</p>
 <ul>
-<li>rather it expects a polymorphic function as its argument</li>
+<li>rather it <strong>demands</strong> a polymorphic function as its argument</li>
 </ul></li>
-<li><p>Let's expand the definition of <code>IdFunc</code> to make this much clearer:</p></li>
+<li><p>Let's expand the type of <code>IdFunc</code> to make this much clearer:</p></li>
 </ul>
 <div class="sourceCode"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span class="ot">someInt ::</span> (forall a<span class="fu">.</span> a <span class="ot">-&gt;</span> a) <span class="ot">-&gt;</span> <span class="dt">Integer</span></code></pre></div>
 </div>
@@ -213,11 +212,11 @@ <h1>Rank-2 and higher polymorphism</h1>
 <h1>Rank-2 and higher polymorphism</h1>
 <div class="sourceCode"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span class="ot">someInt ::</span> (forall a<span class="fu">.</span> a <span class="ot">-&gt;</span> a) <span class="ot">-&gt;</span> <span class="dt">Integer</span></code></pre></div>
 <ul>
-<li><p>This function is completely <strong>monomorphic</strong> (its type is not quantified)</p></li>
-<li><p>When we apply a polymorphic function like <code>id</code> we get to choose which types to instantiate</p></li>
-<li><p>The someInt function does not give us such a choice</p>
+<li><p>This function is completely <strong>monomorphic</strong> (its type is not quantified)</p>
 <ul>
-<li><p>In fact it <strong>requires us</strong> to pass a sufficiently polymorphic function to it such that it can make that choice</p></li>
+<li><p>When we apply a polymorphic function like <code>id</code> we get to choose which types to instantiate</p></li>
+<li><p>The someInt function does not give us such a choice</p></li>
+<li><p>In fact it <strong>demands us</strong> to pass a sufficiently polymorphic function to it such that it can make that choice</p></li>
 <li><p>When we <strong>apply</strong> it, we need to <strong>give it choice</strong></p></li>
 </ul></li>
 <li><p>Let's look at it in terms of <strong>promise / demand </strong>:</p>
@@ -242,7 +241,7 @@ <h1>Rank-2 and higher polymorphism</h1>
 <ul>
 <li>This function is <strong>rank-3 polymorphic</strong></li>
 </ul>
-<div class="sourceCode"><pre class="sourceCode literate haskell"><code class="sourceCode haskell"><span class="ot">someOtherInt ::</span> ((forall a<span class="fu">.</span> a <span class="ot">-&gt;</span> a) <span class="ot">-&gt;</span> <span class="dt">Integer</span>) <span class="ot">-&gt;</span> <span class="dt">Integer</span></code></pre></div>
+<div class="sourceCode"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span class="ot">someOtherInt ::</span> ((forall a<span class="fu">.</span> a <span class="ot">-&gt;</span> a) <span class="ot">-&gt;</span> <span class="dt">Integer</span>) <span class="ot">-&gt;</span> <span class="dt">Integer</span></code></pre></div>
 </div>
 <div id="rankntypes-and-lenses" class="slide section level1">
 <h1>RankNTypes and Lenses</h1>
diff --git a/rankntypes/rankntypes.lhs b/rankntypes/rankntypes.lhs
index 0aeb739..703b07f 100644
--- a/rankntypes/rankntypes.lhs
+++ b/rankntypes/rankntypes.lhs
@@ -1,6 +1,6 @@
 % RankNTypes (second step in the path to lenses)
-% Juan Manuel Gimeno
-% 2 May 2018
+% Juan Manuel Gimeno Illa
+% 9 May 2018
 
 Index
 =====
@@ -13,14 +13,16 @@ Index
 Language extensions
 ===================
 
-* Haskell is a __well defined__ Language
+* Haskell is defined (althought not formally) in
 
     - [Haskell '98 Report](https://www.haskell.org/onlinereport/)
     - [Haskell 2010 Report](https://www.haskell.org/onlinereport/haskell2010/)
 
 * But Haskell was meant to be a playground for experimenting with new functional constructs
 
-* So GHC embraced the notion of extensions: opt-in functionality that gives the user even more tools when writing their programs
+* So GHC embraced the notion of extensions: 
+
+    * opt-in functionality that gives the user even more tools when writing their programs
 
 * The extension that we'll need to use for representing lenses is one that allows __higher rank polymorphism__:
 
@@ -42,14 +44,14 @@ Monomorphism
 > intId :: Integer -> Integer
 > intId x = x
 
-* `intId` is a fully defined value (a function) od a fully defined type `Integer -> Integer`
+* `intId` is a fully defined value (a function) of a fully defined type `Integer -> Integer`
 
 > doubleId :: Double -> Double
 > doubleId x = x
 
-* This is a complete different value of a completely different types
+* This is a complete different value of a completely different type
 
-    - But their definitions are exactly the same?
+    - __But their definitions are exactly the same !!????__
 
 Polymorphism
 ============
@@ -59,28 +61,24 @@ Polymorphism
 > id :: a -> a
 > id x = x
 
-* The definition is still the same
-
 * This kind of polymorphism is called __parametric polimorphism__ (in other languages known as _generics_)
 
-* __Haskell will only allow this if there is indeed a single definition__
+* Haskell will only allow this if there is indeed a __single definition__
 
     * You cannot choose the defintion based on its type
 
 * It also adds safety through a property called __parametricity__:
 
-    * If we pretend there are no loops or exceptions, then the function __fully determined__ by its type.
+    * If we pretend there are no loops or exceptions, then the `id` function is __fully determined__ by its type.
 
     * So, if we see the type `a -> a` it must be the identity function !!!
 
 Rank-1 polymorphism
 ===================
 
-* Usuelly the cal `id` __the identity function__ but in fact we should think of it as a __whole family of functions__
-
-    * we should really say there is a function __for all__ types a
+* Usually we calll `id` __the identity function__ but in fact we should think of it as a __whole family of functions__
 
-    * that is, for every type `a`, there is and identity function called `id`, which is of type `a -> a`
+    * that is, __for all__ type `a`, there is and identity function called `id`, which is of type `a -> a`
 
 * This is the view of the type-checker and by turning the `RankNtypes` extension we can be explicit about it
 
@@ -109,18 +107,18 @@ Rank-1 polymorphism
 
 < print (id (3 :: Integer), id "blah")
 
-* Another way to look at it is in terms of __promise and demand__
+* Another way to look at it is in terms of __promise__ and __demand__
 
     - the __type signature__ of `id` __promises__ that the definition works __for all types__
 
-    - when you actually __apply__ the function you __demand a certain type__
+    - when you actually __apply__ the function to a value, you __demand for a certain type__
 
-    - This interpretation will be very useful when we move to higher-rank polymorphism
+* This interpretation will be very useful when we move to higher-rank polymorphism
 
 Rank-2 and higher polymorphism
 ==============================
 
-* Let's us the explicitness of the quantifier in a type alias
+* Let's use the explicitness of the quantifier in a type alias
 
 > type IdFunc = forall a. a -> a
 
@@ -135,29 +133,30 @@ id x = x
 
 > someInt :: IdFunc -> Integer
 
-* Since any value of type `IdFunc` must be the identity funcion, `someInt` is a function which expects the identity function as its argument and returns an Integer
+* Since any value of type `IdFunc` must be the identity function, `someInt` is a function which expects the identity function as its argument and returns an Integer
 
-* Let's give it some _arbitray_ definition
+* Let's give it some _arbitrary_ definition
 
 > someInt id' = id' 3
 
 Rank-2 and higher polymorphism
 ==============================
 
-* Let's give it some _arbitrary_ definition
-
-> someInt id' = id' 3
+```haskell
+someInt :: IdFunc -> Integer
+someInt id' = id' 3
+```
 
-* This is something new that we didn’t have before !!!!
+* This is __something new__ that we didn’t have before !!!!
 
     - `someInt` has received a function `id'` about which it knows that it is the fully fledged polymorphic identity function
     - so __it can instantiate its type variable as it likes__, and it does so.
 
 * The someInt function isn’t even polymorphic !!!!
 
-    - rather it expects a polymorphic function as its argument
+    - rather it __demands__ a polymorphic function as its argument
 
-* Let's expand the definition of `IdFunc` to make this much clearer:
+* Let's expand the type of `IdFunc` to make this much clearer:
 
 ```haskell
 someInt :: (forall a. a -> a) -> Integer
@@ -172,11 +171,11 @@ someInt :: (forall a. a -> a) -> Integer
 
 * This function is completely __monomorphic__ (its type is not quantified)
 
-* When we apply a polymorphic function like `id` we get to choose which types to instantiate
+    - When we apply a polymorphic function like `id` we get to choose which types to instantiate
 
-* The someInt function does not give us such a choice
+    - The someInt function does not give us such a choice
 
-    - In fact it __requires us__ to pass a sufficiently polymorphic function to it such that it can make that choice
+    - In fact it __demands us__ to pass a sufficiently polymorphic function to it such that it can make that choice
 
     - When we __apply__ it, we need to __give it choice__
 
@@ -202,7 +201,9 @@ Rank-2 and higher polymorphism
 
 * This function is __rank-3 polymorphic__
 
-> someOtherInt :: ((forall a. a -> a) -> Integer) -> Integer
+```haskell
+someOtherInt :: ((forall a. a -> a) -> Integer) -> Integer
+```
 
 RankNTypes and Lenses
 =====================
diff --git a/rankntypes/scripts/slidy.js b/rankntypes/scripts/slidy.js
new file mode 100644
index 0000000..4aa4e6f
--- /dev/null
+++ b/rankntypes/scripts/slidy.js
@@ -0,0 +1,3078 @@
+/* slidy.js
+
+   Copyright (c) 2005-2013 W3C (MIT, ERCIM, Keio), All Rights Reserved.
+   W3C liability, trademark, document use and software licensing
+   rules apply, see:
+
+   http://www.w3.org/Consortium/Legal/copyright-documents
+   http://www.w3.org/Consortium/Legal/copyright-software
+
+   Defines single name "w3c_slidy" in global namespace
+   Adds event handlers without trampling on any others
+*/
+
+// the slidy object implementation
+var w3c_slidy = {
+  // classify which kind of browser we're running under
+  ns_pos: (typeof window.pageYOffset!='undefined'),
+  khtml: ((navigator.userAgent).indexOf("KHTML") >= 0 ? true : false),
+  opera: ((navigator.userAgent).indexOf("Opera") >= 0 ? true : false),
+  ipad: ((navigator.userAgent).indexOf("iPad") >= 0 ? true : false),
+  iphone: ((navigator.userAgent).indexOf("iPhone") >= 0 ? true : false),
+  android: ((navigator.userAgent).indexOf("Android") >= 0 ? true : false),
+  ie: (typeof document.all != "undefined" && !this.opera),
+  ie6: (!this.ns_pos && navigator.userAgent.indexOf("MSIE 6") != -1),
+  ie7: (!this.ns_pos && navigator.userAgent.indexOf("MSIE 7") != -1),
+  ie8: (!this.ns_pos && navigator.userAgent.indexOf("MSIE 8") != -1),
+  ie9: (!this.ns_pos && navigator.userAgent.indexOf("MSIE 9") != -1),
+
+  // data for swipe and double tap detection on touch screens
+  last_tap: 0,
+  prev_tap: 0,
+  start_x: 0,
+  start_y: 0,
+  delta_x: 0,
+  delta_y: 0,
+
+  // are we running as XHTML? (doesn't work on Opera)
+  is_xhtml: /xml/.test(document.contentType),
+
+  slide_number: 0, // integer slide count: 0, 1, 2, ...
+  slide_number_element: null, // element containing slide number
+  slides: [], // set to array of slide div's
+  notes: [], // set to array of handout div's
+  backgrounds: [], // set to array of background div's
+  observers: [], // list of observer functions
+  toolbar: null, // element containing toolbar
+  title: null, // document title
+  last_shown: null, // last incrementally shown item
+  eos: null,  // span element for end of slide indicator
+  toc: null, // table of contents
+  outline: null, // outline element with the focus
+  selected_text_len: 0, // length of drag selection on document
+  view_all: 0,  // 1 to view all slides + handouts
+  want_toolbar: true,  // user preference to show/hide toolbar
+  mouse_click_enabled: true, // enables left click for next slide
+  scroll_hack: 0, // IE work around for position: fixed
+  disable_slide_click: false,  // used by clicked anchors
+
+  lang: "en", // updated to language specified by html file
+
+  help_anchor: null, // used for keyboard focus hack in showToolbar()
+  help_page: "http://www.w3.org/Talks/Tools/Slidy2/help/help.html",
+  help_text: "Navigate with mouse click, space bar, Cursor Left/Right, " +
+             "or Pg Up and Pg Dn. Use S and B to change font size.",
+
+  size_index: 0,
+  size_adjustment: 0,
+  sizes:  new Array("10pt", "12pt", "14pt", "16pt", "18pt", "20pt",
+                    "22pt", "24pt", "26pt", "28pt", "30pt", "32pt"),
+
+  // needed for efficient resizing
+  last_width: 0,
+  last_height: 0,
+
+
+  // Needed for cross browser support for relative width/height on
+  // object elements. The work around is to save width/height attributes
+  // and then to recompute absolute width/height dimensions on resizing
+   objects: [],
+
+  // attach initialiation event handlers
+  set_up: function () {
+    var init = function() { w3c_slidy.init(); };
+    if (typeof window.addEventListener != "undefined")
+      window.addEventListener("load", init, false);
+    else
+      window.attachEvent("onload", init);
+  },
+
+  hide_slides: function () {
+    if (document.body && !w3c_slidy.initialized)
+      document.body.style.visibility = "hidden";
+    else
+      setTimeout(w3c_slidy.hide_slides, 50);
+  },
+
+  // hack to persuade IE to compute correct document height
+  // as needed for simulating fixed positioning of toolbar
+  ie_hack: function () {
+    window.resizeBy(0,-1);
+    window.resizeBy(0, 1);
+  },
+
+  init: function () {
+    //alert("slidy starting test 10");
+    document.body.style.visibility = "visible";
+    this.init_localization();
+    this.add_toolbar();
+    this.wrap_implicit_slides();
+    this.collect_slides();
+    this.collect_notes();
+    this.collect_backgrounds();
+    this.objects = document.body.getElementsByTagName("object");
+    this.patch_anchors();
+    this.slide_number = this.find_slide_number(location.href);
+    window.offscreenbuffering = true;
+    this.size_adjustment = this.find_size_adjust();
+    this.time_left = this.find_duration();
+    this.hide_image_toolbar();  // suppress IE image toolbar popup
+    this.init_outliner();  // activate fold/unfold support
+    this.title = document.title;
+    this.keyboardless = (this.ipad||this.iphone||this.android);
+
+    if (this.keyboardless)
+    {
+      w3c_slidy.remove_class(w3c_slidy.toolbar, "hidden")
+      this.want_toolbar = 0;
+    }
+
+    // work around for opera bug
+    this.is_xhtml = (document.body.tagName == "BODY" ? false : true);
+
+    if (this.slides.length > 0)
+    {
+      var slide = this.slides[this.slide_number];
+   
+      if (this.slide_number > 0)
+      {
+        this.set_visibility_all_incremental("visible");
+        this.last_shown = this.previous_incremental_item(null);
+        this.set_eos_status(true);
+      }
+      else
+      {
+        this.last_shown = null;
+        this.set_visibility_all_incremental("hidden");
+        this.set_eos_status(!this.next_incremental_item(this.last_shown));
+      }
+
+      this.set_location();
+      this.add_class(this.slides[0], "first-slide");
+      w3c_slidy.show_slide(slide);
+    }
+
+    this.toc = this.table_of_contents();
+
+    this.add_initial_prompt();
+
+    // bind event handlers without interfering with custom page scripts
+    // Tap events behave too weirdly to support clicks reliably on
+    // iPhone and iPad, so exclude these from click handler
+
+    if (!this.keyboardless)
+    {
+      this.add_listener(document.body, "click", this.mouse_button_click);
+      this.add_listener(document.body, "mousedown", this.mouse_button_down);
+    }
+
+    this.add_listener(document, "keydown", this.key_down);
+    this.add_listener(document, "keypress", this.key_press);
+    this.add_listener(window, "resize", this.resized);
+    this.add_listener(window, "scroll", this.scrolled);
+    this.add_listener(window, "unload", this.unloaded);
+
+    this.add_listener(document, "gesturechange", function ()
+    {
+      return false;
+    });
+
+    this.attach_touch_handers(this.slides);
+
+    // this seems to be a debugging hack
+    //if (!document.body.onclick)
+    //  document.body.onclick = function () { };
+
+    this.single_slide_view();
+
+    //this.set_location();
+
+    this.resized();
+
+    if (this.ie7)
+      setTimeout(w3c_slidy.ie_hack, 100);
+
+    this.show_toolbar();
+
+    // for back button detection
+    setInterval(function () { w3c_slidy.check_location(); }, 200);
+    w3c_slidy.initialized = true;
+  },
+
+  // create div element with links to each slide
+  table_of_contents: function () {
+    var toc = this.create_element("div");
+    this.add_class(toc, "slidy_toc hidden");
+    //toc.setAttribute("tabindex", "0");
+
+    var heading = this.create_element("div");
+    this.add_class(heading, "toc-heading");
+    heading.innerHTML = this.localize("Table of Contents");
+
+    toc.appendChild(heading);
+    var previous = null;
+
+    for (var i = 0; i < this.slides.length; ++i)
+    {
+      var title = this.has_class(this.slides[i], "title");
+      var num = document.createTextNode((i + 1) + ". ");
+
+      toc.appendChild(num);
+
+      var a = this.create_element("a");
+      a.setAttribute("href", "#(" + (i+1) + ")");
+
+      if (title)
+        this.add_class(a, "titleslide");
+
+      var name = document.createTextNode(this.slide_name(i));
+      a.appendChild(name);
+      a.onclick = w3c_slidy.toc_click;
+      a.onkeydown = w3c_slidy.toc_key_down;
+      a.previous = previous;
+
+      if (previous)
+        previous.next = a;
+
+      toc.appendChild(a);
+
+      if (i == 0)
+        toc.first = a;
+
+      if (i < this.slides.length - 1)
+      {
+        var br = this.create_element("br");
+        toc.appendChild(br);
+      }
+
+      previous = a;
+    }
+
+    toc.focus = function () {
+      if (this.first)
+        this.first.focus();
+    }
+
+    toc.onmouseup = w3c_slidy.mouse_button_up;
+
+    toc.onclick = function (e) {
+      e||(e=window.event);
+
+      if (w3c_slidy.selected_text_len <= 0)
+         w3c_slidy.hide_table_of_contents(true);
+
+      w3c_slidy.stop_propagation(e);
+    
+      if (e.cancel != undefined)
+        e.cancel = true;
+      
+      if (e.returnValue != undefined)
+        e.returnValue = false;
+      
+      return false;
+    };
+
+    document.body.insertBefore(toc, document.body.firstChild);
+    return toc;
+  },
+
+  is_shown_toc: function () {
+    return !w3c_slidy.has_class(w3c_slidy.toc, "hidden");
+  },
+
+  show_table_of_contents: function () {
+    w3c_slidy.remove_class(w3c_slidy.toc, "hidden");
+    var toc = w3c_slidy.toc;
+    toc.focus();
+
+    if (w3c_slidy.ie7 && w3c_slidy.slide_number == 0)
+      setTimeout(w3c_slidy.ie_hack, 100);
+  },
+
+  hide_table_of_contents: function (focus) {
+    w3c_slidy.add_class(w3c_slidy.toc, "hidden");
+
+    if (focus && !w3c_slidy.opera &&
+        !w3c_slidy.has_class(w3c_slidy.toc, "hidden"))
+      w3c_slidy.set_focus();
+  },
+
+  toggle_table_of_contents: function () {
+    if (w3c_slidy.is_shown_toc())
+      w3c_slidy.hide_table_of_contents(true);
+    else
+      w3c_slidy.show_table_of_contents();
+  },
+
+  // called on clicking toc entry
+  toc_click: function (e) {
+    if (!e)
+      e = window.event;
+
+    var target = w3c_slidy.get_target(e);
+
+    if (target && target.nodeType == 1)
+    {
+      var uri = target.getAttribute("href");
+
+      if (uri)
+      {
+        //alert("going to " + uri);
+        var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+        w3c_slidy.hide_slide(slide);
+        w3c_slidy.slide_number = w3c_slidy.find_slide_number(uri);
+        slide = w3c_slidy.slides[w3c_slidy.slide_number];
+        w3c_slidy.last_shown = null;
+        w3c_slidy.set_location();
+        w3c_slidy.set_visibility_all_incremental("hidden");
+        w3c_slidy.set_eos_status(!w3c_slidy.next_incremental_item(w3c_slidy.last_shown));
+        w3c_slidy.show_slide(slide);
+        //target.focus();
+
+        try
+        {
+          if (!w3c_slidy.opera)
+            w3c_slidy.set_focus();
+        }
+        catch (e)
+        {
+        }
+      }
+    }
+
+    w3c_slidy.hide_table_of_contents(true);
+    if (w3c_slidy.ie7) w3c_slidy.ie_hack();
+    w3c_slidy.stop_propagation(e);
+    return w3c_slidy.cancel(e);
+  },
+
+  // called onkeydown for toc entry
+  toc_key_down: function (event) {
+    var key;
+
+    if (!event)
+      var event = window.event;
+
+    // kludge around NS/IE differences 
+    if (window.event)
+      key = window.event.keyCode;
+    else if (event.which)
+      key = event.which;
+    else
+      return true; // Yikes! unknown browser
+
+    // ignore event if key value is zero
+    // as for alt on Opera and Konqueror
+    if (!key)
+      return true;
+
+    // check for concurrent control/command/alt key
+    // but are these only present on mouse events?
+
+    if (event.ctrlKey || event.altKey)
+      return true;
+
+    if (key == 13)
+    {
+      var uri = this.getAttribute("href");
+
+      if (uri)
+      {
+        //alert("going to " + uri);
+       var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+        w3c_slidy.hide_slide(slide);
+        w3c_slidy.slide_number = w3c_slidy.find_slide_number(uri);
+        slide = w3c_slidy.slides[w3c_slidy.slide_number];
+        w3c_slidy.last_shown = null;
+        w3c_slidy.set_location();
+        w3c_slidy.set_visibility_all_incremental("hidden");
+        w3c_slidy.set_eos_status(!w3c_slidy.next_incremental_item(w3c_slidy.last_shown));
+        w3c_slidy.show_slide(slide);
+        //target.focus();
+
+        try
+        {
+          if (!w3c_slidy.opera)
+            w3c_slidy.set_focus();
+        }
+        catch (e)
+        {
+        }
+      }
+
+      w3c_slidy.hide_table_of_contents(true);
+
+      if (self.ie7)
+       w3c_slidy.ie_hack();
+
+      return w3c_slidy.cancel(event);
+    }
+
+    if (key == 40 && this.next)
+    {
+      this.next.focus();
+      return w3c_slidy.cancel(event);
+    }
+
+    if (key == 38 && this.previous)
+    {
+      this.previous.focus();
+      return w3c_slidy.cancel(event);
+    }
+
+    return true;
+  },
+
+  touchstart: function (e)
+  {
+    // a double touch often starts with a
+    // single touch due to fingers touching
+    // down at slightly different times
+    // thus avoid calling preventDefault here
+    this.prev_tap = this.last_tap;
+    this.last_tap = (new Date).getTime();
+
+    var tap_delay = this.last_tap - this.prev_tap;
+
+    if (tap_delay <= 200)
+    {
+      // double tap
+    }
+
+    var touch = e.touches[0];
+
+    this.pageX = touch.pageX;
+    this.pageY = touch.pageY;
+    this.screenX = touch.screenX;
+    this.screenY = touch.screenY;
+    this.clientX = touch.clientX;
+    this.clientY = touch.clientY;
+
+    this.delta_x = this.delta_y = 0;
+  },
+
+  touchmove: function (e)
+  {
+    // override native gestures for single touch
+    if (e.touches.length > 1)
+      return;
+
+    e.preventDefault();
+    var touch = e.touches[0];
+    this.delta_x = touch.pageX - this.pageX;
+    this.delta_y = touch.pageY - this.pageY;
+  },
+
+  touchend: function (e)
+  {
+    // default behavior for multi-touch
+    if (e.touches.length > 1)
+      return;
+
+    var delay = (new Date).getTime() - this.last_tap;
+    var dx = this.delta_x;
+    var dy = this.delta_y;
+    var abs_dx = Math.abs(dx);
+    var abs_dy = Math.abs(dy);
+
+    if (delay < 500 && (abs_dx > 100 || abs_dy > 100))
+    {
+      if (abs_dx > 0.5 * abs_dy)
+      {
+        e.preventDefault();
+
+        if (dx < 0)
+          w3c_slidy.next_slide(true);
+        else
+          w3c_slidy.previous_slide(true);
+      }
+      else if (abs_dy > 2 * abs_dx)
+      {
+        e.preventDefault();
+        w3c_slidy.toggle_table_of_contents();
+      }
+    }
+  },
+
+  // ### OBSOLETE ###
+  before_print: function () {
+    this.show_all_slides();
+    this.hide_toolbar();
+    alert("before print");
+  },
+
+  // ### OBSOLETE ###
+  after_print: function () {
+    if (!this.view_all)
+    {
+      this.single_slide_view();
+      this.show_toolbar();
+    }
+    alert("after print");
+  },
+
+  // ### OBSOLETE ###
+  print_slides: function () {
+    this.before_print();
+    window.print();
+    this.after_print();
+  },
+
+  // ### OBSOLETE ?? ###
+  toggle_view: function () {
+    if (this.view_all)
+    {
+      this.single_slide_view();
+      this.show_toolbar();
+      this.view_all = 0;
+    }
+    else
+    {
+      this.show_all_slides();
+      this.hide_toolbar();
+      this.view_all = 1;
+    }
+  },
+
+  // prepare for printing  ### OBSOLETE ###
+  show_all_slides: function () {
+    this.remove_class(document.body, "single_slide");
+    this.set_visibility_all_incremental("visible");
+  },
+
+  // restore after printing  ### OBSOLETE ###
+  single_slide_view: function () {
+    this.add_class(document.body, "single_slide");
+    this.set_visibility_all_incremental("visible");
+    this.last_shown = this.previous_incremental_item(null);
+  },
+
+  // suppress IE's image toolbar pop up
+  hide_image_toolbar: function () {
+    if (!this.ns_pos)
+    {
+      var images = document.getElementsByTagName("IMG");
+
+      for (var i = 0; i < images.length; ++i)
+        images[i].setAttribute("galleryimg", "no");
+    }
+  },
+
+  unloaded: function (e) {
+    //alert("unloaded");
+  },
+
+  // Safari and Konqueror don't yet support getComputedStyle()
+  // and they always reload page when location.href is updated
+  is_KHTML: function () {
+    var agent = navigator.userAgent;
+    return (agent.indexOf("KHTML") >= 0 ? true : false);
+  },
+
+  // find slide name from first h1 element
+  // default to document title + slide number
+  slide_name: function (index) {
+    var name = null;
+    var slide = this.slides[index];
+
+    var heading = this.find_heading(slide);
+
+    if (heading)
+      name = this.extract_text(heading);
+
+    if (!name)
+      name = this.title + "(" + (index + 1) + ")";
+
+    name.replace(/\&/g, "&amp;");
+    name.replace(/\</g, "&lt;");
+    name.replace(/\>/g, "&gt;");
+
+    return name;
+  },
+
+  // find first h1 element in DOM tree
+  find_heading: function (node) {
+    if (!node || node.nodeType != 1)
+      return null;
+
+    if (node.nodeName == "H1" || node.nodeName == "h1")
+      return node;
+
+    var child = node.firstChild;
+
+    while (child)
+    {
+      node = this.find_heading(child);
+
+      if (node)
+        return node;
+
+      child = child.nextSibling;
+    }
+
+    return null;
+  },
+
+  // recursively extract text from DOM tree
+  extract_text: function (node) {
+    if (!node)
+      return "";
+
+    // text nodes
+    if (node.nodeType == 3)
+      return node.nodeValue;
+
+    // elements
+    if (node.nodeType == 1)
+    {
+      node = node.firstChild;
+      var text = "";
+
+      while (node)
+      {
+        text = text + this.extract_text(node);
+        node = node.nextSibling;
+      }
+
+      return text;
+    }
+
+    return "";
+  },
+
+  // find copyright text from meta element
+  find_copyright: function () {
+    var name, content;
+    var meta = document.getElementsByTagName("meta");
+
+    for (var i = 0; i < meta.length; ++i)
+    {
+      name = meta[i].getAttribute("name");
+      content = meta[i].getAttribute("content");
+
+      if (name == "copyright")
+        return content;
+    }
+
+    return null;
+  },
+
+  find_size_adjust: function () {
+    var name, content, offset;
+    var meta = document.getElementsByTagName("meta");
+
+    for (var i = 0; i < meta.length; ++i)
+    {
+      name = meta[i].getAttribute("name");
+      content = meta[i].getAttribute("content");
+
+      if (name == "font-size-adjustment")
+        return 1 * content;
+    }
+
+    return 1;
+  },
+
+  // <meta name="duration" content="20" />  for 20 minutes
+  find_duration: function () {
+    var name, content, offset;
+    var meta = document.getElementsByTagName("meta");
+
+    for (var i = 0; i < meta.length; ++i)
+    {
+      name = meta[i].getAttribute("name");
+      content = meta[i].getAttribute("content");
+
+      if (name == "duration")
+        return 60000 * content;
+    }
+
+    return null;
+  },
+
+  replace_by_non_breaking_space: function (str) {
+    for (var i = 0; i < str.length; ++i)
+      str[i] = 160;
+  },
+
+  // ### CHECK ME ### is use of "li" okay for text/html?
+  // for XHTML do we also need to specify namespace?
+  init_outliner: function () {
+    var items = document.getElementsByTagName("li");
+
+    for (var i = 0; i < items.length; ++i)
+    {
+      var target = items[i];
+
+      if (!this.has_class(target.parentNode, "outline"))
+        continue;
+
+      target.onclick = this.outline_click;
+/* ### more work needed for IE6
+      if (!this.ns_pos)
+      {
+        target.onmouseover = this.hover_outline;
+        target.onmouseout = this.unhover_outline;
+      }
+*/
+      if (this.foldable(target))
+      {
+        target.foldable = true;
+        target.onfocus = function () {w3c_slidy.outline = this;};
+        target.onblur = function () {w3c_slidy.outline = null;};
+
+        if (!target.getAttribute("tabindex"))
+          target.setAttribute("tabindex", "0");
+
+        if (this.has_class(target, "expand"))
+          this.unfold(target);
+        else
+          this.fold(target);
+      }
+      else
+      {
+        this.add_class(target, "nofold");
+        target.visible = true;
+        target.foldable = false;
+      }
+    }
+  },
+
+  foldable: function (item) {
+    if (!item || item.nodeType != 1)
+      return false;
+
+    var node = item.firstChild;
+
+    while (node)
+    {
+      if (node.nodeType == 1 && this.is_block(node))
+        return true;
+
+      node = node.nextSibling;
+    }
+
+    return false;
+  },
+
+  // ### CHECK ME ### switch to add/remove "hidden" class
+  fold: function (item) {
+    if (item)
+    {
+      this.remove_class(item, "unfolded");
+      this.add_class(item, "folded");
+    }
+
+    var node = item ? item.firstChild : null;
+
+    while (node)
+    {
+      if (node.nodeType == 1 && this.is_block(node)) // element
+      {
+         w3c_slidy.add_class(node, "hidden");
+      }
+
+      node = node.nextSibling;
+    }
+
+    item.visible = false;
+  },
+
+  // ### CHECK ME ### switch to add/remove "hidden" class
+  unfold: function (item) {
+    if (item)
+    {
+      this.add_class(item, "unfolded");
+      this.remove_class(item, "folded");
+    }
+
+    var node = item ? item.firstChild : null;
+
+    while (node)
+    {
+      if (node.nodeType == 1 && this.is_block(node)) // element
+      {
+        w3c_slidy.remove_class(node, "hidden");
+      }
+
+      node = node.nextSibling;
+    }
+
+    item.visible = true;
+  },
+
+  outline_click: function (e) {
+    if (!e)
+      e = window.event;
+
+    var rightclick = false;
+    var target = w3c_slidy.get_target(e);
+
+    while (target && target.visible == undefined)
+      target = target.parentNode;
+
+    if (!target)
+      return true;
+
+    if (e.which)
+      rightclick = (e.which == 3);
+    else if (e.button)
+      rightclick = (e.button == 2);
+
+    if (!rightclick && target.visible != undefined)
+    {
+      if (target.foldable)
+      {
+        if (target.visible)
+          w3c_slidy.fold(target);
+        else
+          w3c_slidy.unfold(target);
+      }
+
+      w3c_slidy.stop_propagation(e);
+      e.cancel = true;
+      e.returnValue = false;
+    }
+
+    return false;
+  },
+
+  add_initial_prompt: function () {
+    var prompt = this.create_element("div");
+    prompt.setAttribute("class", "initial_prompt");
+
+    var p1 = this.create_element("p");
+    prompt.appendChild(p1);
+    p1.setAttribute("class", "help");
+
+    if (this.keyboardless)
+      p1.innerHTML = "swipe left to move to next slide";
+    else
+      p1.innerHTML = "Space, Right Arrow or swipe left to move to " +
+                     "next slide, click help below for more details";
+
+    this.add_listener(prompt, "click", function (e) {
+      document.body.removeChild(prompt);
+      w3c_slidy.stop_propagation(e);
+    
+      if (e.cancel != undefined)
+        e.cancel = true;
+      
+      if (e.returnValue != undefined)
+        e.returnValue = false;
+      
+      return false;
+    });
+
+    document.body.appendChild(prompt);
+    this.initial_prompt = prompt;
+    setTimeout(function() {document.body.removeChild(prompt);}, 5000);
+  },
+
+  add_toolbar: function () {
+    var counter, page;
+
+     this.toolbar = this.create_element("div");
+     this.toolbar.setAttribute("class", "toolbar");
+
+     // a reasonably behaved browser
+     if (this.ns_pos || !this.ie6)
+     {
+       var right = this.create_element("div");
+       right.setAttribute("style", "float: right; text-align: right");
+
+       counter = this.create_element("span")
+       counter.innerHTML = this.localize("slide") + " n/m";
+       right.appendChild(counter);
+       this.toolbar.appendChild(right);
+
+       var left = this.create_element("div");
+       left.setAttribute("style", "text-align: left");
+
+       // global end of slide indicator
+       this.eos = this.create_element("span");
+       this.eos.innerHTML = "* ";
+       left.appendChild(this.eos);
+
+       var help = this.create_element("a");
+       help.setAttribute("href", this.help_page);
+       help.setAttribute("title", this.localize(this.help_text));
+       help.innerHTML = this.localize("help?");
+       left.appendChild(help);
+       this.help_anchor = help;  // save for focus hack
+
+       var gap1 = document.createTextNode(" ");
+       left.appendChild(gap1);
+
+       var contents = this.create_element("a");
+       contents.setAttribute("href", "javascript:w3c_slidy.toggle_table_of_contents()");
+       contents.setAttribute("title", this.localize("table of contents"));
+       contents.innerHTML = this.localize("contents?");
+       left.appendChild(contents);
+
+       var gap2 = document.createTextNode(" ");
+       left.appendChild(gap2);
+
+       var copyright = this.find_copyright();
+
+       if (copyright)
+       {
+         var span = this.create_element("span");
+         span.className = "copyright";
+         span.innerHTML = copyright;
+         left.appendChild(span);
+       }
+
+       this.toolbar.setAttribute("tabindex", "0");
+       this.toolbar.appendChild(left);
+     }
+     else // IE6 so need to work around its poor CSS support
+     {
+       this.toolbar.style.position = (this.ie7 ? "fixed" : "absolute");
+       this.toolbar.style.zIndex = "200";
+       this.toolbar.style.width = "99.9%";
+       this.toolbar.style.height = "1.2em";
+       this.toolbar.style.top = "auto";
+       this.toolbar.style.bottom = "0";
+       this.toolbar.style.left = "0";
+       this.toolbar.style.right = "0";
+       this.toolbar.style.textAlign = "left";
+       this.toolbar.style.fontSize = "60%";
+       this.toolbar.style.color = "red";
+       this.toolbar.borderWidth = 0;
+       this.toolbar.className = "toolbar";
+       this.toolbar.style.background = "rgb(240,240,240)";
+
+       // would like to have help text left aligned
+       // and page counter right aligned, floating
+       // div's don't work, so instead use nested
+       // absolutely positioned div's.
+
+       var sp = this.create_element("span");
+       sp.innerHTML = "&nbsp;&nbsp;*&nbsp;";
+       this.toolbar.appendChild(sp);
+       this.eos = sp;  // end of slide indicator
+
+       var help = this.create_element("a");
+       help.setAttribute("href", this.help_page);
+       help.setAttribute("title", this.localize(this.help_text));
+       help.innerHTML = this.localize("help?");
+       this.toolbar.appendChild(help);
+       this.help_anchor = help;  // save for focus hack
+
+       var gap1 = document.createTextNode(" ");
+       this.toolbar.appendChild(gap1);
+
+       var contents = this.create_element("a");
+       contents.setAttribute("href", "javascript:toggleTableOfContents()");
+       contents.setAttribute("title", this.localize("table of contents".localize));
+       contents.innerHTML = this.localize("contents?");
+       this.toolbar.appendChild(contents);
+
+       var gap2 = document.createTextNode(" ");
+       this.toolbar.appendChild(gap2);
+
+       var copyright = this.find_copyright();
+
+       if (copyright)
+       {
+         var span = this.create_element("span");
+         span.innerHTML = copyright;
+         span.style.color = "black";
+         span.style.marginLeft = "0.5em";
+         this.toolbar.appendChild(span);
+       }
+
+       counter = this.create_element("div")
+       counter.style.position = "absolute";
+       counter.style.width = "auto"; //"20%";
+       counter.style.height = "1.2em";
+       counter.style.top = "auto";
+       counter.style.bottom = 0;
+       counter.style.right = "0";
+       counter.style.textAlign = "right";
+       counter.style.color = "red";
+       counter.style.background = "rgb(240,240,240)";
+
+       counter.innerHTML = this.localize("slide") + " n/m";
+       this.toolbar.appendChild(counter);
+     }
+
+     // ensure that click isn't passed through to the page
+     this.toolbar.onclick =
+         function (e) {
+           if (!e)
+             e = window.event;
+
+           var target = e.target;
+
+           if (!target && e.srcElement)
+             target = e.srcElement;
+
+           // work around Safari bug
+           if (target && target.nodeType == 3)
+             target = target.parentNode;
+
+           w3c_slidy.stop_propagation(e);
+
+           if (target && target.nodeName.toLowerCase() != "a")
+             w3c_slidy.mouse_button_click(e);
+         };
+
+     this.slide_number_element = counter;
+     this.set_eos_status(false);
+     document.body.appendChild(this.toolbar);
+  },
+
+  // wysiwyg editors make it hard to use div elements
+  // e.g. amaya loses the div when you copy and paste
+  // this function wraps div elements around implicit
+  // slides which start with an h1 element and continue
+  // up to the next heading or div element
+  wrap_implicit_slides: function () {
+    var i, heading, node, next, div;
+    var headings = document.getElementsByTagName("h1");
+
+    if (!headings)
+      return;
+
+    for (i = 0; i < headings.length; ++i)
+    {
+      heading = headings[i];
+
+      if (heading.parentNode != document.body)
+        continue;
+
+      node = heading.nextSibling;
+
+      div = document.createElement("div");
+      this.add_class(div, "slide");
+      document.body.replaceChild(div, heading);
+      div.appendChild(heading);
+
+      while (node)
+      {
+        if (node.nodeType == 1) // an element
+        {
+           if (node.nodeName == "H1" || node.nodeName == "h1")
+             break;
+
+           if (node.nodeName == "DIV" || node.nodeName == "div")
+           {
+             if (this.has_class(node, "slide"))
+               break;
+
+             if (this.has_class(node, "handout"))
+               break;
+           }
+        }
+
+        next = node.nextSibling;
+        node = document.body.removeChild(node);
+        div.appendChild(node);
+        node = next;
+      } 
+    }
+  },
+
+  attach_touch_handers: function(slides)
+  {
+    var i, slide;
+
+    for (i = 0; i < slides.length; ++i)
+    {
+      slide = slides[i];
+      this.add_listener(slide, "touchstart", this.touchstart);
+      this.add_listener(slide, "touchmove", this.touchmove);
+      this.add_listener(slide, "touchend", this.touchend);
+    }
+  },
+
+// return new array of all slides
+  collect_slides: function () {
+    var slides = new Array();
+    var divs = document.body.getElementsByTagName("div");
+
+    for (var i = 0; i < divs.length; ++i)
+    {
+      div = divs.item(i);
+
+      if (this.has_class(div, "slide"))
+      {
+        // add slide to collection
+        slides[slides.length] = div;
+
+        // hide each slide as it is found
+        this.add_class(div, "hidden");
+
+        // add dummy <br/> at end for scrolling hack
+        var node1 = document.createElement("br");
+        div.appendChild(node1);
+        var node2 = document.createElement("br");
+        div.appendChild(node2);
+      }
+      else if (this.has_class(div, "background"))
+      {  // work around for Firefox SVG reload bug
+        // which otherwise replaces 1st SVG graphic with 2nd
+        div.style.display = "block";
+      }
+    }
+
+    this.slides = slides;
+  },
+
+  // return new array of all <div class="handout">
+  collect_notes: function () {
+    var notes = new Array();
+    var divs = document.body.getElementsByTagName("div");
+
+    for (var i = 0; i < divs.length; ++i)
+    {
+      div = divs.item(i);
+
+      if (this.has_class(div, "handout"))
+      {
+        // add note to collection
+        notes[notes.length] = div;
+
+        // and hide it
+        this.add_class(div, "hidden");
+      }
+    }
+
+    this.notes = notes;
+  },
+
+  // return new array of all <div class="background">
+  // including named backgrounds e.g. class="background titlepage"
+  collect_backgrounds: function () {
+    var backgrounds = new Array();
+    var divs = document.body.getElementsByTagName("div");
+
+    for (var i = 0; i < divs.length; ++i)
+    {
+      div = divs.item(i);
+
+      if (this.has_class(div, "background"))
+      {
+        // add background to collection
+        backgrounds[backgrounds.length] = div;
+
+        // and hide it
+        this.add_class(div, "hidden");
+      }
+    }
+
+    this.backgrounds = backgrounds;
+  },
+
+  // set click handlers on all anchors
+  patch_anchors: function () {
+    var self = w3c_slidy;
+    var handler = function (event) {
+      // compare this.href with location.href
+      // for link to another slide in this doc
+
+      if (self.page_address(this.href) == self.page_address(location.href))
+      {
+        // yes, so find new slide number
+        var newslidenum = self.find_slide_number(this.href);
+
+        if (newslidenum != self.slide_number)
+        {
+          var slide = self.slides[self.slide_number];
+          self.hide_slide(slide);
+          self.slide_number = newslidenum;
+          slide = self.slides[self.slide_number];
+          self.show_slide(slide);
+          self.set_location();
+        }
+      }
+      else
+        w3c_slidy.stop_propagation(event);
+
+//      else if (this.target == null)
+//        location.href = this.href;
+
+      this.blur();
+      self.disable_slide_click = true;
+    };
+
+    var anchors = document.body.getElementsByTagName("a");
+
+    for (var i = 0; i < anchors.length; ++i)
+    {
+      if (window.addEventListener)
+        anchors[i].addEventListener("click", handler, false);
+      else
+        anchors[i].attachEvent("onclick", handler);
+    }
+  },
+
+  // ### CHECK ME ### see which functions are invoked via setTimeout
+  // either directly or indirectly for use of w3c_slidy vs this
+  show_slide_number: function () {
+    var timer = w3c_slidy.get_timer();
+    w3c_slidy.slide_number_element.innerHTML = timer + w3c_slidy.localize("slide") + " " +
+           (w3c_slidy.slide_number + 1) + "/" + w3c_slidy.slides.length;
+  },
+
+  // every 200mS check if the location has been changed as a
+  // result of the user activating the Back button/menu item
+  // doesn't work for Opera < 9.5
+  check_location: function () {
+    var hash = location.hash;
+
+    if (w3c_slidy.slide_number > 0 && (hash == "" || hash == "#"))
+      w3c_slidy.goto_slide(0);
+    else if (hash.length > 2 && hash != "#("+(w3c_slidy.slide_number+1)+")")
+    {
+      var num = parseInt(location.hash.substr(2));
+
+      if (!isNaN(num))
+        w3c_slidy.goto_slide(num-1);
+    }
+
+    if (w3c_slidy.time_left && w3c_slidy.slide_number > 0)
+    {
+      w3c_slidy.show_slide_number();
+
+      if (w3c_slidy.time_left > 0)
+        w3c_slidy.time_left -= 200;
+    } 
+  },
+
+  get_timer: function () {
+    var timer = "";
+    if (w3c_slidy.time_left)
+    {
+      var mins, secs;
+      secs = Math.floor(w3c_slidy.time_left/1000);
+      mins = Math.floor(secs / 60);
+      secs = secs % 60;
+      timer = (mins ? mins+"m" : "") + secs + "s ";
+    }
+
+    return timer;
+  },
+
+  // this doesn't push location onto history stack for IE
+  // for which a hidden iframe hack is needed: load page into
+  // the iframe with script that set's parent's location.hash
+  // but that won't work for standalone use unless we can
+  // create the page dynamically via a javascript: URL
+  // ### use history.pushState if available
+  set_location: function () {
+     var uri = w3c_slidy.page_address(location.href);
+     var hash = "#(" + (w3c_slidy.slide_number+1) + ")";
+
+     if (w3c_slidy.slide_number >= 0)
+       uri = uri + hash;
+
+     if (typeof(history.pushState) != "undefined")
+     {
+       document.title = w3c_slidy.title + " (" + (w3c_slidy.slide_number+1) + ")";
+       history.pushState(0, document.title, hash);
+       w3c_slidy.show_slide_number();
+       w3c_slidy.notify_observers();
+       return;
+     }
+
+     if (w3c_slidy.ie && (w3c_slidy.ie6 || w3c_slidy.ie7))
+       w3c_slidy.push_hash(hash);
+
+     if (uri != location.href) // && !khtml
+        location.href = uri;
+
+     if (this.khtml)
+        hash = "(" + (w3c_slidy.slide_number+1) + ")";
+
+     if (!this.ie && location.hash != hash && location.hash != "")
+       location.hash = hash;
+
+     document.title = w3c_slidy.title + " (" + (w3c_slidy.slide_number+1) + ")";
+     w3c_slidy.show_slide_number();
+     w3c_slidy.notify_observers();
+  },
+
+  notify_observers: function ()
+  {
+    var slide = this.slides[this.slide_number];
+
+    for (var i = 0; i < this.observers.length; ++i)
+      this.observers[i](this.slide_number+1, this.find_heading(slide).innerText, location.href);
+  },
+
+  add_observer: function (observer)
+  {
+    for (var i = 0; i < this.observers.length; ++i)
+    {
+      if (observer == this.observers[i])
+        return;
+    }
+
+    this.observers.push(observer);
+  },
+
+  remove_observer: function (o)
+  {
+    for (var i = 0; i < this.observers.length; ++i)
+    {
+      if (observer == this.observers[i])
+      {
+        this.observers.splice(i,1);
+        break;
+      }
+    }
+  },
+
+  page_address: function (uri) {
+    var i = uri.indexOf("#");
+
+    if (i < 0)
+      i = uri.indexOf("%23");
+
+    // check if anchor is entire page
+
+    if (i < 0)
+      return uri;  // yes
+
+    return uri.substr(0, i);
+  },
+
+  // only used for IE6 and IE7
+  on_frame_loaded: function (hash) {
+    location.hash = hash;
+    var uri = w3c_slidy.page_address(location.href);
+    location.href = uri + hash;
+  },
+
+  // history hack with thanks to Bertrand Le Roy
+  push_hash: function (hash) {
+    if (hash == "") hash = "#(1)";
+      window.location.hash = hash;
+
+    var doc = document.getElementById("historyFrame").contentWindow.document;
+    doc.open("javascript:'<html></html>'");
+    doc.write("<html><head><script type=\"text/javascript\">window.parent.w3c_slidy.on_frame_loaded('"+
+      (hash) + "');</script></head><body>hello mum</body></html>");
+      doc.close();
+  },
+
+  // find current slide based upon location
+  // first find target anchor and then look
+  // for associated div element enclosing it
+  // finally map that to slide number
+  find_slide_number: function (uri) {
+    // first get anchor from page location
+
+    var i = uri.indexOf("#");
+
+    // check if anchor is entire page
+    if (i < 0)
+      return 0;  // yes
+
+    var anchor = unescape(uri.substr(i+1));
+
+    // now use anchor as XML ID to find target
+    var target = document.getElementById(anchor);
+
+    if (!target)
+    {
+      // does anchor look like "(2)" for slide 2 ??
+      // where first slide is (1)
+      var re = /\((\d)+\)/;
+
+      if (anchor.match(re))
+      {
+        var num = parseInt(anchor.substring(1, anchor.length-1));
+
+        if (num > this.slides.length)
+          num = 1;
+
+        if (--num < 0)
+          num = 0;
+
+        return num;
+      }
+
+      // accept [2] for backwards compatibility
+      re = /\[(\d)+\]/;
+
+      if (anchor.match(re))
+      {
+         var num = parseInt(anchor.substring(1, anchor.length-1));
+
+         if (num > this.slides.length)
+            num = 1;
+
+         if (--num < 0)
+            num = 0;
+
+         return num;
+      }
+
+      // oh dear unknown anchor
+      return 0;
+    }
+
+    // search for enclosing slide
+
+    while (true)
+    {
+      // browser coerces html elements to uppercase!
+      if (target.nodeName.toLowerCase() == "div" &&
+            this.has_class(target, "slide"))
+      {
+        // found the slide element
+        break;
+      }
+
+      // otherwise try parent element if any
+
+      target = target.parentNode;
+
+      if (!target)
+      {
+        return 0;   // no luck!
+      }
+    };
+
+    for (i = 0; i < slides.length; ++i)
+    {
+      if (slides[i] == target)
+        return i;  // success
+    }
+
+    // oh dear still no luck
+    return 0;
+  },
+
+  previous_slide: function (incremental) {
+    if (!w3c_slidy.view_all)
+    {
+      var slide;
+
+      if ((incremental || w3c_slidy.slide_number == 0) && w3c_slidy.last_shown != null)
+      {
+        w3c_slidy.last_shown = w3c_slidy.hide_previous_item(w3c_slidy.last_shown);
+        w3c_slidy.set_eos_status(false);
+      }
+      else if (w3c_slidy.slide_number > 0)
+      {
+        slide = w3c_slidy.slides[w3c_slidy.slide_number];
+        w3c_slidy.hide_slide(slide);
+
+        w3c_slidy.slide_number = w3c_slidy.slide_number - 1;
+        slide = w3c_slidy.slides[w3c_slidy.slide_number];
+        w3c_slidy.set_visibility_all_incremental("visible");
+        w3c_slidy.last_shown = w3c_slidy.previous_incremental_item(null);
+        w3c_slidy.set_eos_status(true);
+        w3c_slidy.show_slide(slide);
+      }
+
+      w3c_slidy.set_location();
+
+      if (!w3c_slidy.ns_pos)
+        w3c_slidy.refresh_toolbar(200);
+    }
+  },
+
+  next_slide: function (incremental) {
+    if (!w3c_slidy.view_all)
+    {
+      var slide, last = w3c_slidy.last_shown;
+
+      if (incremental || w3c_slidy.slide_number == w3c_slidy.slides.length - 1)
+         w3c_slidy.last_shown = w3c_slidy.reveal_next_item(w3c_slidy.last_shown);
+
+      if ((!incremental || w3c_slidy.last_shown == null) &&
+             w3c_slidy.slide_number < w3c_slidy.slides.length - 1)
+      {
+         slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.hide_slide(slide);
+
+         w3c_slidy.slide_number = w3c_slidy.slide_number + 1;
+         slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.last_shown = null;
+         w3c_slidy.set_visibility_all_incremental("hidden");
+         w3c_slidy.show_slide(slide);
+      }
+      else if (!w3c_slidy.last_shown)
+      {
+         if (last && incremental)
+           w3c_slidy.last_shown = last;
+      }
+
+      w3c_slidy.set_location();
+
+      w3c_slidy.set_eos_status(!w3c_slidy.next_incremental_item(w3c_slidy.last_shown));
+
+      if (!w3c_slidy.ns_pos)
+         w3c_slidy.refresh_toolbar(200);
+     }
+  },
+
+  // to first slide with nothing revealed
+  // i.e. state at start of presentation
+  first_slide: function () {
+     if (!w3c_slidy.view_all)
+     {
+       var slide;
+
+       if (w3c_slidy.slide_number != 0)
+       {
+         slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.hide_slide(slide);
+
+         w3c_slidy.slide_number = 0;
+         slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.last_shown = null;
+         w3c_slidy.set_visibility_all_incremental("hidden");
+         w3c_slidy.show_slide(slide);
+       }
+
+       w3c_slidy.set_eos_status(
+         !w3c_slidy.next_incremental_item(w3c_slidy.last_shown));
+       w3c_slidy.set_location();
+     }
+  },
+
+  // goto last slide with everything revealed
+  // i.e. state at end of presentation
+  last_slide: function () {
+    if (!w3c_slidy.view_all)
+    {
+      var slide;
+
+      w3c_slidy.last_shown = null; //revealNextItem(lastShown);
+
+      if (w3c_slidy.last_shown == null &&
+          w3c_slidy.slide_number < w3c_slidy.slides.length - 1)
+      {
+         slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.hide_slide(slide);
+         w3c_slidy.slide_number = w3c_slidy.slides.length - 1;
+         slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.set_visibility_all_incremental("visible");
+         w3c_slidy.last_shown = w3c_slidy.previous_incremental_item(null);
+
+         w3c_slidy.show_slide(slide);
+      }
+      else
+      {
+         w3c_slidy.set_visibility_all_incremental("visible");
+         w3c_slidy.last_shown = w3c_slidy.previous_incremental_item(null);
+      }
+
+      w3c_slidy.set_eos_status(true);
+      w3c_slidy.set_location();
+    }
+  },
+
+
+  // ### check this and consider add/remove class
+  set_eos_status: function (state) {
+    if (this.eos)
+      this.eos.style.color = (state ? "rgb(240,240,240)" : "red");
+  },
+
+  // first slide is 0
+  goto_slide: function (num) {
+    //alert("going to slide " + (num+1));
+    var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+    w3c_slidy.hide_slide(slide);
+    w3c_slidy.slide_number = num;
+    slide = w3c_slidy.slides[w3c_slidy.slide_number];
+    w3c_slidy.last_shown = null;
+    w3c_slidy.set_visibility_all_incremental("hidden");
+    w3c_slidy.set_eos_status(!w3c_slidy.next_incremental_item(w3c_slidy.last_shown));
+    document.title = w3c_slidy.title + " (" + (w3c_slidy.slide_number+1) + ")";
+    w3c_slidy.show_slide(slide);
+    w3c_slidy.show_slide_number();
+  },
+
+
+  show_slide: function (slide) {
+    this.sync_background(slide);
+    this.remove_class(slide, "hidden");
+
+    // work around IE9 object rendering bug
+    setTimeout("window.scrollTo(0,0);", 1);
+  },
+
+  hide_slide: function (slide) {
+    this.add_class(slide, "hidden");
+  },
+
+  set_focus: function (element)
+  {
+    if (element)
+      element.focus();
+    else
+    {
+      w3c_slidy.help_anchor.focus();
+
+      setTimeout(function() {
+        w3c_slidy.help_anchor.blur();
+      }, 1);
+    }
+  },
+
+  // show just the backgrounds pertinent to this slide
+  // when slide background-color is transparent
+  // this should now work with rgba color values
+  sync_background: function (slide) {
+    var background;
+    var bgColor;
+
+    if (slide.currentStyle)
+      bgColor = slide.currentStyle["backgroundColor"];
+    else if (document.defaultView)
+    {
+      var styles = document.defaultView.getComputedStyle(slide,null);
+
+      if (styles)
+        bgColor = styles.getPropertyValue("background-color");
+      else // broken implementation probably due Safari or Konqueror
+      {
+        //alert("defective implementation of getComputedStyle()");
+        bgColor = "transparent";
+      }
+    }
+    else
+      bgColor == "transparent";
+
+    if (bgColor == "transparent" ||
+        bgColor.indexOf("rgba") >= 0 ||
+        bgColor.indexOf("opacity") >= 0)
+    {
+      var slideClass = this.get_class_list(slide);
+
+      for (var i = 0; i < this.backgrounds.length; i++)
+      {
+        background = this.backgrounds[i];
+
+        var bgClass = this.get_class_list(background);
+
+        if (this.matching_background(slideClass, bgClass))
+          this.remove_class(background, "hidden");
+        else
+          this.add_class(background, "hidden");
+      }
+    }
+    else // forcibly hide all backgrounds
+      this.hide_backgrounds();
+  },
+
+  hide_backgrounds: function () {
+    for (var i = 0; i < this.backgrounds.length; i++)
+    {
+      background = this.backgrounds[i];
+      this.add_class(background, "hidden");
+    }
+  },
+
+  // compare classes for slide and background
+  matching_background: function (slideClass, bgClass) {
+    var i, count, pattern, result;
+
+    // define pattern as regular expression
+    pattern = /\w+/g;
+
+    // check background class names
+    result = bgClass.match(pattern);
+
+    for (i = count = 0; i < result.length; i++)
+    {
+      if (result[i] == "hidden")
+        continue;
+
+      if (result[i] == "background")
+	continue;
+
+      ++count;
+    }
+
+    if (count == 0)  // default match
+      return true;
+
+    // check for matches and place result in array
+    result = slideClass.match(pattern);
+
+    // now check if desired name is present for background
+    for (i = count = 0; i < result.length; i++)
+    {
+      if (result[i] == "hidden")
+        continue;
+
+      if (this.has_token(bgClass, result[i]))
+        return true;
+    }
+
+    return false;
+  },
+
+  resized: function () {
+     var width = 0;
+
+     if ( typeof( window.innerWidth ) == 'number' )
+       width = window.innerWidth;  // Non IE browser
+     else if (document.documentElement && document.documentElement.clientWidth)
+       width = document.documentElement.clientWidth;  // IE6
+     else if (document.body && document.body.clientWidth)
+       width = document.body.clientWidth; // IE4
+
+     var height = 0;
+
+     if ( typeof( window.innerHeight ) == 'number' )
+       height = window.innerHeight;  // Non IE browser
+     else if (document.documentElement && document.documentElement.clientHeight)
+       height = document.documentElement.clientHeight;  // IE6
+     else if (document.body && document.body.clientHeight)
+       height = document.body.clientHeight; // IE4
+
+     if (height && (width/height > 1.05*1024/768))
+     {
+       width = height * 1024.0/768;
+     }
+
+     // IE fires onresize even when only font size is changed!
+     // so we do a check to avoid blocking < and > actions
+     if (width != w3c_slidy.last_width || height != w3c_slidy.last_height)
+     {
+       if (width >= 1100)
+         w3c_slidy.size_index = 5;    // 4
+       else if (width >= 1000)
+         w3c_slidy.size_index = 4;    // 3
+       else if (width >= 800)
+         w3c_slidy.size_index = 3;    // 2
+       else if (width >= 600)
+         w3c_slidy.size_index = 2;    // 1
+       else if (width)
+         w3c_slidy.size_index = 0;
+
+       // add in font size adjustment from meta element e.g.
+       // <meta name="font-size-adjustment" content="-2" />
+       // useful when slides have too much content ;-)
+
+       if (0 <= w3c_slidy.size_index + w3c_slidy.size_adjustment &&
+             w3c_slidy.size_index + w3c_slidy.size_adjustment < w3c_slidy.sizes.length)
+         w3c_slidy.size_index = w3c_slidy.size_index + w3c_slidy.size_adjustment;
+
+       // enables cross browser use of relative width/height
+       // on object elements for use with SVG and Flash media
+       w3c_slidy.adjust_object_dimensions(width, height);
+
+       if (document.body.style.fontSize != w3c_slidy.sizes[w3c_slidy.size_index])
+       {
+         document.body.style.fontSize = w3c_slidy.sizes[w3c_slidy.size_index];
+       }
+
+       w3c_slidy.last_width = width;
+       w3c_slidy.last_height = height;
+
+       // force reflow to work around Mozilla bug
+       if (w3c_slidy.ns_pos)
+       {
+         var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+         w3c_slidy.hide_slide(slide);
+         w3c_slidy.show_slide(slide);
+       }
+
+       // force correct positioning of toolbar
+       w3c_slidy.refresh_toolbar(200);
+     }
+  },
+
+  scrolled: function () {
+    if (w3c_slidy.toolbar && !w3c_slidy.ns_pos && !w3c_slidy.ie7)
+    {
+      w3c_slidy.hack_offset = w3c_slidy.scroll_x_offset();
+      // hide toolbar
+      w3c_slidy.toolbar.style.display = "none";
+
+      // make it reappear later
+      if (w3c_slidy.scrollhack == 0 && !w3c_slidy.view_all)
+      {
+        setTimeout(function () {w3c_slidy.show_toolbar(); }, 1000);
+        w3c_slidy.scrollhack = 1;
+      }
+    }
+  },
+
+  hide_toolbar: function () {
+    w3c_slidy.add_class(w3c_slidy.toolbar, "hidden");
+    window.focus();
+  },
+
+  // used to ensure IE refreshes toolbar in correct position
+  refresh_toolbar: function (interval) {
+    if (!w3c_slidy.ns_pos && !w3c_slidy.ie7)
+    {
+      w3c_slidy.hide_toolbar();
+      setTimeout(function () {w3c_slidy.show_toolbar();}, interval);
+    }
+  },
+
+  // restores toolbar after short delay
+  show_toolbar: function () {
+    if (w3c_slidy.want_toolbar)
+    {
+      w3c_slidy.toolbar.style.display = "block";
+
+      if (!w3c_slidy.ns_pos)
+      {
+        // adjust position to allow for scrolling
+        var xoffset = w3c_slidy.scroll_x_offset();
+        w3c_slidy.toolbar.style.left = xoffset;
+        w3c_slidy.toolbar.style.right = xoffset;
+
+        // determine vertical scroll offset
+        //var yoffset = scrollYOffset();
+
+        // bottom is doc height - window height - scroll offset
+        //var bottom = documentHeight() - lastHeight - yoffset
+
+        //if (yoffset > 0 || documentHeight() > lastHeight)
+        //   bottom += 16;  // allow for height of scrollbar
+
+        w3c_slidy.toolbar.style.bottom = 0; //bottom;
+      }
+
+      w3c_slidy.remove_class(w3c_slidy.toolbar, "hidden");
+    }
+
+    w3c_slidy.scrollhack = 0;
+
+
+    // set the keyboard focus to the help link on the
+    // toolbar to ensure that document has the focus
+    // IE doesn't always work with window.focus()
+    // and this hack has benefit of Enter for help
+
+    try
+    {
+      if (!w3c_slidy.opera)
+        w3c_slidy.set_focus();
+    }
+    catch (e)
+    {
+    }
+  },
+
+// invoked via F key
+  toggle_toolbar: function () {
+    if (!w3c_slidy.view_all)
+    {
+      if (w3c_slidy.has_class(w3c_slidy.toolbar, "hidden"))
+      {
+        w3c_slidy.remove_class(w3c_slidy.toolbar, "hidden")
+        w3c_slidy.want_toolbar = 1;
+      }
+      else
+      {
+        w3c_slidy.add_class(w3c_slidy.toolbar, "hidden")
+        w3c_slidy.want_toolbar = 0;
+      }
+    }
+  },
+
+  scroll_x_offset: function () {
+    if (window.pageXOffset)
+      return self.pageXOffset;
+
+    if (document.documentElement && 
+             document.documentElement.scrollLeft)
+      return document.documentElement.scrollLeft;
+
+    if (document.body)
+      return document.body.scrollLeft;
+
+    return 0;
+  },
+
+  scroll_y_offset: function () {
+    if (window.pageYOffset)
+      return self.pageYOffset;
+
+    if (document.documentElement && 
+             document.documentElement.scrollTop)
+      return document.documentElement.scrollTop;
+
+    if (document.body)
+      return document.body.scrollTop;
+
+    return 0;
+  },
+
+  // looking for a way to determine height of slide content
+  // the slide itself is set to the height of the window
+  optimize_font_size: function () {
+    var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+
+    //var dh = documentHeight(); //getDocHeight(document);
+    var dh = slide.scrollHeight;
+    var wh = getWindowHeight();
+    var u = 100 * dh / wh;
+
+    alert("window utilization = " + u + "% (doc "
+      + dh + " win " + wh + ")");
+  },
+
+  // from document object
+  get_doc_height: function (doc) {
+    if (!doc)
+      doc = document;
+
+    if (doc && doc.body && doc.body.offsetHeight)
+      return doc.body.offsetHeight;  // ns/gecko syntax
+
+    if (doc && doc.body && doc.body.scrollHeight)
+      return doc.body.scrollHeight;
+
+    alert("couldn't determine document height");
+  },
+
+  get_window_height: function () {
+    if ( typeof( window.innerHeight ) == 'number' )
+      return window.innerHeight;  // Non IE browser
+
+    if (document.documentElement && document.documentElement.clientHeight)
+      return document.documentElement.clientHeight;  // IE6
+
+    if (document.body && document.body.clientHeight)
+      return document.body.clientHeight; // IE4
+  },
+
+  document_height: function () {
+    var sh, oh;
+
+    sh = document.body.scrollHeight;
+    oh = document.body.offsetHeight;
+
+    if (sh && oh)
+    {
+      return (sh > oh ? sh : oh);
+    }
+
+    // no idea!
+    return 0;
+  },
+
+  smaller: function () {
+    if (w3c_slidy.size_index > 0)
+    {
+      --w3c_slidy.size_index;
+    }
+
+    w3c_slidy.toolbar.style.display = "none";
+    document.body.style.fontSize = w3c_slidy.sizes[w3c_slidy.size_index];
+    var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+    w3c_slidy.hide_slide(slide);
+    w3c_slidy.show_slide(slide);
+    setTimeout(function () {w3c_slidy.show_toolbar(); }, 50);
+  },
+
+  bigger: function () {
+    if (w3c_slidy.size_index < w3c_slidy.sizes.length - 1)
+    {
+      ++w3c_slidy.size_index;
+    }
+
+    w3c_slidy.toolbar.style.display = "none";
+    document.body.style.fontSize = w3c_slidy.sizes[w3c_slidy.size_index];
+    var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+    w3c_slidy.hide_slide(slide);
+    w3c_slidy.show_slide(slide);
+    setTimeout(function () {w3c_slidy.show_toolbar(); }, 50);
+  },
+
+  // enables cross browser use of relative width/height
+  // on object elements for use with SVG and Flash media
+  // with thanks to Ivan Herman for the suggestion
+  adjust_object_dimensions: function (width, height) {
+    for( var i = 0; i < w3c_slidy.objects.length; i++ )
+    {
+      var obj = this.objects[i];
+      var mimeType = obj.getAttribute("type");
+
+      if (mimeType == "image/svg+xml" || mimeType == "application/x-shockwave-flash")
+      {
+        if ( !obj.initialWidth ) 
+          obj.initialWidth = obj.getAttribute("width");
+
+        if ( !obj.initialHeight ) 
+          obj.initialHeight = obj.getAttribute("height");
+
+        if ( obj.initialWidth && obj.initialWidth.charAt(obj.initialWidth.length-1) == "%" )
+        {
+          var w = parseInt(obj.initialWidth.slice(0, obj.initialWidth.length-1));
+          var newW = width * (w/100.0);
+          obj.setAttribute("width",newW);
+        }
+
+        if ( obj.initialHeight &&
+             obj.initialHeight.charAt(obj.initialHeight.length-1) == "%" )
+        {
+          var h = parseInt(obj.initialHeight.slice(0, obj.initialHeight.length-1));
+          var newH = height * (h/100.0);
+          obj.setAttribute("height", newH);
+        }
+      }
+    }
+  },
+
+  // needed for Opera to inhibit default behavior
+  // since Opera delivers keyPress even if keyDown
+  // was cancelled
+  key_press: function (event) {
+    if (!event)
+      event = window.event;
+
+    if (!w3c_slidy.key_wanted)
+      return w3c_slidy.cancel(event);
+
+    return true;
+  },
+
+  //  See e.g. http://www.quirksmode.org/js/events/keys.html for keycodes
+  key_down: function (event) {
+    var key, target, tag;
+
+    w3c_slidy.key_wanted = true;
+
+    if (!event)
+      event = window.event;
+
+    // kludge around NS/IE differences 
+    if (window.event)
+    {
+      key = window.event.keyCode;
+      target = window.event.srcElement;
+    }
+    else if (event.which)
+    {
+      key = event.which;
+      target = event.target;
+    }
+    else
+      return true; // Yikes! unknown browser
+
+    // ignore event if key value is zero
+    // as for alt on Opera and Konqueror
+    if (!key)
+       return true;
+
+    // avoid interfering with keystroke
+    // behavior for non-slidy chrome elements
+    if (!w3c_slidy.slidy_chrome(target) &&
+        w3c_slidy.special_element(target))
+      return true;
+
+    // check for concurrent control/command/alt key
+    // but are these only present on mouse events?
+
+    if (event.ctrlKey || event.altKey || event.metaKey)
+       return true;
+
+    // dismiss table of contents if visible
+    if (w3c_slidy.is_shown_toc() && key != 9 && key != 16 && key != 38 && key != 40)
+    {
+      w3c_slidy.hide_table_of_contents(true);
+
+      if (key == 27 || key == 84 || key == 67)
+        return w3c_slidy.cancel(event);
+    }
+
+    if (key == 34) // Page Down
+    {
+      if (w3c_slidy.view_all)
+        return true;
+
+      w3c_slidy.next_slide(false);
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 33) // Page Up
+    {
+      if (w3c_slidy.view_all)
+        return true;
+
+      w3c_slidy.previous_slide(false);
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 32) // space bar
+    {
+      w3c_slidy.next_slide(true);
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 37) // Left arrow
+    {
+      w3c_slidy.previous_slide(!event.shiftKey);
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 36) // Home
+    {
+      w3c_slidy.first_slide();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 35) // End
+    {
+      w3c_slidy.last_slide();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 39) // Right arrow
+    {
+      w3c_slidy.next_slide(!event.shiftKey);
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 13) // Enter
+    {
+      if (w3c_slidy.outline)
+      {
+        if (w3c_slidy.outline.visible)
+          w3c_slidy.fold(w3c_slidy.outline);
+        else
+          w3c_slidy.unfold(w3c_slidy.outline);
+          
+       return w3c_slidy.cancel(event);
+      }
+    }
+    else if (key == 188)  // < for smaller fonts
+    {
+      w3c_slidy.smaller();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 190)  // > for larger fonts
+    {
+      w3c_slidy.bigger();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 189 || key == 109)  // - for smaller fonts
+    {
+      w3c_slidy.smaller();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 187 || key == 191 || key == 107)  // = +  for larger fonts
+    {
+      w3c_slidy.bigger();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 83)  // S for smaller fonts
+    {
+      w3c_slidy.smaller();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 66)  // B for larger fonts
+    {
+      w3c_slidy.bigger();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 90)  // Z for last slide
+    {
+      w3c_slidy.last_slide();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 70)  // F for toggle toolbar
+    {
+      w3c_slidy.toggle_toolbar();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 65)  // A for toggle view single/all slides
+    {
+      w3c_slidy.toggle_view();
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 75)  // toggle action of left click for next page
+    {
+      w3c_slidy.mouse_click_enabled = !w3c_slidy.mouse_click_enabled;
+      var alert_msg = (w3c_slidy.mouse_click_enabled ?
+                "enabled" : "disabled") +  " mouse click advance";
+
+      alert(w3c_slidy.localize(alert_msg));
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 84 || key == 67)  // T or C for table of contents
+    {
+      if (w3c_slidy.toc)
+        w3c_slidy.toggle_table_of_contents();
+
+      return w3c_slidy.cancel(event);
+    }
+    else if (key == 72) // H for help
+    {
+      window.location = w3c_slidy.help_page;
+      return w3c_slidy.cancel(event);
+    }
+    //else alert("key code is "+ key);
+
+    return true;
+  },
+
+  // safe for both text/html and application/xhtml+xml
+  create_element: function (name) {
+    if (this.xhtml && (typeof document.createElementNS != 'undefined'))
+      return document.createElementNS("http://www.w3.org/1999/xhtml", name)
+
+    return document.createElement(name);
+  },
+
+  get_element_style: function (elem, IEStyleProp, CSSStyleProp) {
+    if (elem.currentStyle)
+    {
+      return elem.currentStyle[IEStyleProp];
+    }
+    else if (window.getComputedStyle)
+    {
+      var compStyle = window.getComputedStyle(elem, "");
+      return compStyle.getPropertyValue(CSSStyleProp);
+    }
+    return "";
+  },
+
+  // the string str is a whitespace separated list of tokens
+  // test if str contains a particular token, e.g. "slide"
+  has_token: function (str, token) {
+    if (str)
+    {
+      // define pattern as regular expression
+      var pattern = /\w+/g;
+
+      // check for matches
+      // place result in array
+      var result = str.match(pattern);
+
+      // now check if desired token is present
+      for (var i = 0; i < result.length; i++)
+      {
+        if (result[i] == token)
+          return true;
+      }
+    }
+
+    return false;
+  },
+
+  get_class_list: function (element) {
+    if (typeof element.className != 'undefined')
+      return element.className;
+
+    return element.getAttribute("class");
+  },
+
+  has_class: function (element, name) {
+    if (element.nodeType != 1)
+      return false;
+
+    var regexp = new RegExp("(^| )" + name + "\W*");
+
+    if (typeof element.className != 'undefined')
+      return regexp.test(element.className);
+
+    return regexp.test(element.getAttribute("class"));
+  },
+
+  remove_class: function (element, name) {
+    var regexp = new RegExp("(^| )" + name + "\W*");
+    var clsval = "";
+
+    if (typeof element.className != 'undefined')
+    {
+      clsval = element.className;
+
+      if (clsval)
+      {
+        clsval = clsval.replace(regexp, "");
+        element.className = clsval;
+      }
+    }
+    else
+    {
+      clsval = element.getAttribute("class");
+
+      if (clsval)
+      {
+        clsval = clsval.replace(regexp, "");
+        element.setAttribute("class", clsval);
+      }
+    }
+  },
+
+  add_class: function (element, name) {
+    if (!this.has_class(element, name))
+    {
+      if (typeof element.className != 'undefined')
+        element.className += " " + name;
+      else
+      {
+        var clsval = element.getAttribute("class");
+        clsval = clsval ? clsval + " " + name : name;
+        element.setAttribute("class", clsval);
+      }
+    }
+  },
+
+  // HTML elements that can be used with class="incremental"
+  // note that you can also put the class on containers like
+  // up, ol, dl, and div to make their contents appear
+  // incrementally. Upper case is used since this is what
+  // browsers report for HTML node names (text/html).
+  incremental_elements: null,
+  okay_for_incremental: function (name) {
+    if (!this.incremental_elements)
+    {
+      var inclist = new Array();
+      inclist["p"] = true;
+      inclist["pre"] = true;
+      inclist["li"] = true;
+      inclist["blockquote"] = true;
+      inclist["dt"] = true;
+      inclist["dd"] = true;
+      inclist["h2"] = true;
+      inclist["h3"] = true;
+      inclist["h4"] = true;
+      inclist["h5"] = true;
+      inclist["h6"] = true;
+      inclist["span"] = true;
+      inclist["address"] = true;
+      inclist["table"] = true;
+      inclist["tr"] = true;
+      inclist["th"] = true;
+      inclist["td"] = true;
+      inclist["img"] = true;
+      inclist["object"] = true;
+      this.incremental_elements = inclist;
+    }
+    return this.incremental_elements[name.toLowerCase()];
+  },
+
+  next_incremental_item: function (node) {
+    var br = this.is_xhtml ? "br" : "BR";
+    var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+
+    for (;;)
+    {
+      node = w3c_slidy.next_node(slide, node);
+
+      if (node == null || node.parentNode == null)
+        break;
+
+      if (node.nodeType == 1)  // ELEMENT
+      {
+        if (node.nodeName == br)
+          continue;
+
+        if (w3c_slidy.has_class(node, "incremental")
+             && w3c_slidy.okay_for_incremental(node.nodeName))
+          return node;
+
+        if (w3c_slidy.has_class(node.parentNode, "incremental")
+             && !w3c_slidy.has_class(node, "non-incremental"))
+          return node;
+      }
+    }
+
+    return node;
+  },
+
+  previous_incremental_item: function (node) {
+    var br = this.is_xhtml ? "br" : "BR";
+    var slide = w3c_slidy.slides[w3c_slidy.slide_number];
+
+    for (;;)
+    {
+      node = w3c_slidy.previous_node(slide, node);
+
+      if (node == null || node.parentNode == null)
+        break;
+
+      if (node.nodeType == 1)
+      {
+        if (node.nodeName == br)
+          continue;
+
+        if (w3c_slidy.has_class(node, "incremental")
+             && w3c_slidy.okay_for_incremental(node.nodeName))
+          return node;
+
+        if (w3c_slidy.has_class(node.parentNode, "incremental")
+             && !w3c_slidy.has_class(node, "non-incremental"))
+          return node;
+      }
+    }
+
+    return node;
+  },
+
+  // set visibility for all elements on current slide with
+  // a parent element with attribute class="incremental"
+  set_visibility_all_incremental: function (value) {
+    var node = this.next_incremental_item(null);
+
+    if (value == "hidden")
+    {
+      while (node)
+      {
+        w3c_slidy.add_class(node, "invisible");
+        node = w3c_slidy.next_incremental_item(node);
+      }
+    }
+    else // value == "visible"
+    {
+      while (node)
+      {
+        w3c_slidy.remove_class(node, "invisible");
+        node = w3c_slidy.next_incremental_item(node);
+      }
+    }
+  },
+
+  // reveal the next hidden item on the slide
+  // node is null or the node that was last revealed
+  reveal_next_item: function (node) {
+    node = w3c_slidy.next_incremental_item(node);
+
+    if (node && node.nodeType == 1)  // an element
+      w3c_slidy.remove_class(node, "invisible");
+
+    return node;
+  },
+
+  // exact inverse of revealNextItem(node)
+  hide_previous_item: function (node) {
+    if (node && node.nodeType == 1)  // an element
+      w3c_slidy.add_class(node, "invisible");
+
+    return this.previous_incremental_item(node);
+  },
+
+  // left to right traversal of root's content
+  next_node: function (root, node) {
+    if (node == null)
+      return root.firstChild;
+
+    if (node.firstChild)
+      return node.firstChild;
+
+    if (node.nextSibling)
+      return node.nextSibling;
+
+    for (;;)
+    {
+      node = node.parentNode;
+
+      if (!node || node == root)
+        break;
+
+      if (node && node.nextSibling)
+        return node.nextSibling;
+    }
+
+    return null;
+  },
+
+  // right to left traversal of root's content
+  previous_node: function (root, node) {
+    if (node == null)
+    {
+      node = root.lastChild;
+
+      if (node)
+      {
+        while (node.lastChild)
+          node = node.lastChild;
+      }
+
+      return node;
+    }
+
+    if (node.previousSibling)
+    {
+      node = node.previousSibling;
+
+      while (node.lastChild)
+        node = node.lastChild;
+
+      return node;
+    }
+
+    if (node.parentNode != root)
+      return node.parentNode;
+
+    return null;
+  },
+
+  previous_sibling_element: function (el) {
+    el = el.previousSibling;
+
+    while (el && el.nodeType != 1)
+      el = el.previousSibling;
+
+    return el;
+  },
+
+  next_sibling_element: function (el) {
+    el = el.nextSibling;
+
+    while (el && el.nodeType != 1)
+      el = el.nextSibling;
+
+    return el;
+  },
+
+  first_child_element: function (el) {
+    var node;
+
+    for (node = el.firstChild; node; node = node.nextSibling)
+    {
+      if (node.nodeType == 1)
+        break;
+    }
+
+    return node;
+  },
+
+  first_tag: function (element, tag) {
+    var node;
+
+    if (!this.is_xhtml)
+      tag = tag.toUpperCase();
+
+    for (node = element.firstChild; node; node = node.nextSibling)
+    {
+      if (node.nodeType == 1 && node.nodeName == tag)
+        break;
+    }
+
+    return node;
+  },
+
+  hide_selection: function () {
+    if (window.getSelection) // Firefox, Chromium, Safari, Opera
+    {
+      var selection = window.getSelection();
+
+      if (selection.rangeCount > 0)
+      {
+        var range = selection.getRangeAt(0);
+        range.collapse (false);
+      }
+    }
+    else // Internet Explorer
+    {
+      var textRange = document.selection.createRange ();
+      textRange.collapse (false);
+    }
+  },
+
+  get_selected_text: function () {
+    try
+    {
+      if (window.getSelection)
+        return window.getSelection().toString();
+
+      if (document.getSelection)
+        return document.getSelection().toString();
+
+      if (document.selection)
+        return document.selection.createRange().text;
+    }
+    catch (e)
+    {
+    }
+
+    return "";
+  },
+
+  // make note of length of selected text
+  // as this evaluates to zero in click event
+  mouse_button_up: function (e) {
+    w3c_slidy.selected_text_len = w3c_slidy.get_selected_text().length;
+  },
+
+  mouse_button_down: function (e) {
+    w3c_slidy.selected_text_len = w3c_slidy.get_selected_text().length;
+    w3c_slidy.mouse_x = e.clientX;
+    w3c_slidy.mouse_y = e.clientY;
+  },
+
+  // right mouse button click is reserved for context menus
+  // it is more reliable to detect rightclick than leftclick
+  mouse_button_click: function (e) {
+    if (!e)
+      var e = window.event;
+
+    if (Math.abs(e.clientX -w3c_slidy.mouse_x) +
+        Math.abs(e.clientY -w3c_slidy.mouse_y) > 10)
+      return true;
+
+    if (w3c_slidy.selected_text_len > 0)
+      return true;
+
+    var rightclick = false;
+    var leftclick = false;
+    var middleclick = false;
+    var target;
+
+    if (!e)
+      var e = window.event;
+
+    if (e.target)
+      target = e.target;
+    else if (e.srcElement)
+      target = e.srcElement;
+
+    // work around Safari bug
+    if (target.nodeType == 3)
+      target = target.parentNode;
+
+    if (e.which) // all browsers except IE
+    {
+      leftclick = (e.which == 1);
+      middleclick = (e.which == 2);
+      rightclick = (e.which == 3);
+    }
+    else if (e.button)
+    {
+      // Konqueror gives 1 for left, 4 for middle
+      // IE6 gives 0 for left and not 1 as I expected
+
+      if (e.button == 4)
+        middleclick = true;
+
+      // all browsers agree on 2 for right button
+      rightclick = (e.button == 2);
+    }
+    else
+      leftclick = true;
+
+    if (w3c_slidy.selected_text_len > 0)
+    {
+      w3c_slidy.stop_propagation(e);
+      e.cancel = true;
+      e.returnValue = false;
+      return false;
+    }
+
+    // dismiss table of contents
+    w3c_slidy.hide_table_of_contents(false);
+
+    // check if target is something that probably want's clicks
+    // e.g. a, embed, object, input, textarea, select, option
+    var tag = target.nodeName.toLowerCase();
+
+    if (w3c_slidy.mouse_click_enabled && leftclick &&
+        !w3c_slidy.special_element(target) &&
+        !target.onclick)
+    {
+      w3c_slidy.next_slide(true);
+      w3c_slidy.stop_propagation(e);
+      e.cancel = true;
+      e.returnValue = false;
+      return false;
+    }
+
+    return true;
+  },
+
+  special_element: function (element) {
+    if (this.has_class(element, "non-interactive"))
+      return false;
+
+    var tag = element.nodeName.toLowerCase();
+
+    return element.onkeydown ||
+      element.onclick ||
+      tag == "a" ||
+      tag == "embed" ||
+      tag == "object" ||
+      tag == "video" ||
+      tag == "audio" ||
+      tag == "svg" ||
+      tag == "canvas" ||
+      tag == "input" ||
+      tag == "textarea" ||
+      tag == "select" ||
+      tag == "option";
+  },
+
+  slidy_chrome: function (el) {
+    while (el)
+    {
+      if (el == w3c_slidy.toc ||
+          el == w3c_slidy.toolbar ||
+          w3c_slidy.has_class(el, "outline"))
+        return true;
+
+      el = el.parentNode;
+    }
+
+    return false;
+  },
+
+  get_key: function (e)
+  {
+    var key;
+
+    // kludge around NS/IE differences 
+    if (typeof window.event != "undefined")
+      key = window.event.keyCode;
+    else if (e.which)
+      key = e.which;
+
+    return key;
+  },
+
+  get_target: function (e) {
+    var target;
+
+    if (!e)
+      e = window.event;
+
+    if (e.target)
+      target = e.target;
+    else if (e.srcElement)
+      target = e.srcElement;
+
+    if (target.nodeType != 1)
+      target = target.parentNode;
+
+    return target;
+  },
+
+  // does display property provide correct defaults?
+  is_block: function (elem) {
+    var tag = elem.nodeName.toLowerCase();
+
+    return tag == "ol" || tag == "ul" || tag == "p" || tag == "dl" ||
+           tag == "li" || tag == "table" || tag == "pre" ||
+           tag == "h1" || tag == "h2" || tag == "h3" ||
+           tag == "h4" || tag == "h5" || tag == "h6" ||
+           tag == "blockquote" || tag == "address"; 
+  },
+
+  add_listener: function (element, event, handler) {
+    if (window.addEventListener)
+      element.addEventListener(event, handler, false);
+    else
+      element.attachEvent("on"+event, handler);
+  },
+
+  // used to prevent event propagation from field controls
+  stop_propagation: function (event) {
+    event = event ? event : window.event;
+    event.cancelBubble = true;  // for IE
+
+    if (event.stopPropagation)
+      event.stopPropagation();
+
+    return true;
+  },
+
+  cancel: function (event) {
+    if (event)
+    {
+       event.cancel = true;
+       event.returnValue = false;
+
+      if (event.preventDefault)
+        event.preventDefault();
+    }
+
+    w3c_slidy.key_wanted = false;
+    return false;
+  },
+
+// for each language define an associative array
+// and also the help text which is longer
+
+  strings_es: {
+    "slide":"pág.",
+    "help?":"Ayuda",
+    "contents?":"Índice",
+    "table of contents":"tabla de contenidos",
+    "Table of Contents":"Tabla de Contenidos",
+    "restart presentation":"Reiniciar presentación",
+    "restart?":"Inicio"
+  },
+  help_es:
+    "Utilice el ratón, barra espaciadora, teclas Izda/Dcha, " +
+    "o Re pág y Av pág. Use S y B para cambiar el tamaño de fuente.",
+
+  strings_ca: {
+    "slide":"pàg..",
+    "help?":"Ajuda",
+    "contents?":"Índex",
+    "table of contents":"taula de continguts",
+    "Table of Contents":"Taula de Continguts",
+    "restart presentation":"Reiniciar presentació",
+    "restart?":"Inici"
+  },
+  help_ca:
+    "Utilitzi el ratolí, barra espaiadora, tecles Esq./Dta. " +
+    "o Re pàg y Av pàg. Usi S i B per canviar grandària de font.",
+
+  strings_cs: {
+    "slide":"snímek",
+    "help?":"nápověda",
+    "contents?":"obsah",
+    "table of contents":"obsah prezentace",
+    "Table of Contents":"Obsah prezentace",
+    "restart presentation":"znovu spustit prezentaci",
+    "restart?":"restart"
+  },
+  help_cs:
+    "Prezentaci můžete procházet pomocí kliknutí myši, mezerníku, " +
+    "šipek vlevo a vpravo nebo kláves PageUp a PageDown. Písmo se " +
+    "dá zvětšit a zmenšit pomocí kláves B a S.",
+
+  strings_nl: {
+    "slide":"pagina",
+    "help?":"Help?",
+    "contents?":"Inhoud?",
+    "table of contents":"inhoudsopgave",
+    "Table of Contents":"Inhoudsopgave",
+    "restart presentation":"herstart presentatie",
+    "restart?":"Herstart?"
+  },
+  help_nl:
+     "Navigeer d.m.v. het muis, spatiebar, Links/Rechts toetsen, " +
+     "of PgUp en PgDn. Gebruik S en B om de karaktergrootte te veranderen.",
+
+  strings_de: {
+    "slide":"Seite",
+    "help?":"Hilfe",
+    "contents?":"Übersicht",
+    "table of contents":"Inhaltsverzeichnis",
+    "Table of Contents":"Inhaltsverzeichnis",
+    "restart presentation":"Präsentation neu starten",
+    "restart?":"Neustart"
+  },
+  help_de:
+    "Benutzen Sie die Maus, Leerschlag, die Cursortasten links/rechts oder " +
+    "Page up/Page Down zum Wechseln der Seiten und S und B für die Schriftgrösse.",
+
+  strings_pl: {
+    "slide":"slajd",
+    "help?":"pomoc?",
+    "contents?":"spis treści?",
+    "table of contents":"spis treści",
+    "Table of Contents":"Spis Treści",
+    "restart presentation":"Restartuj prezentację",
+    "restart?":"restart?"
+  },
+  help_pl:
+    "Zmieniaj slajdy klikając myszą, naciskając spację, strzałki lewo/prawo" +
+    "lub PgUp / PgDn. Użyj klawiszy S i B, aby zmienić rozmiar czczionki.",
+
+  strings_fr: {
+    "slide":"page",
+    "help?":"Aide",
+    "contents?":"Index",
+    "table of contents":"table des matières",
+    "Table of Contents":"Table des matières",
+    "restart presentation":"Recommencer l'exposé",
+    "restart?":"Début"
+  },
+  help_fr:
+    "Naviguez avec la souris, la barre d'espace, les flèches " +
+    "gauche/droite ou les touches Pg Up, Pg Dn. Utilisez " +
+    "les touches S et B pour modifier la taille de la police.",
+
+  strings_hu: {
+    "slide":"oldal",
+    "help?":"segítség",
+    "contents?":"tartalom",
+    "table of contents":"tartalomjegyzék",
+    "Table of Contents":"Tartalomjegyzék",
+    "restart presentation":"bemutató újraindítása",
+    "restart?":"újraindítás"
+  },
+  help_hu:
+    "Az oldalak közti lépkedéshez kattintson az egérrel, vagy " +
+    "használja a szóköz, a bal, vagy a jobb nyíl, illetve a Page Down, " +
+    "Page Up billentyűket. Az S és a B billentyűkkel változtathatja " +
+    "a szöveg méretét.",
+
+  strings_it: {
+    "slide":"pag.",
+    "help?":"Aiuto",
+    "contents?":"Indice",
+    "table of contents":"indice",
+    "Table of Contents":"Indice",
+    "restart presentation":"Ricominciare la presentazione",
+    "restart?":"Inizio"
+  },
+  help_it:
+    "Navigare con mouse, barra spazio, frecce sinistra/destra o " +
+    "PgUp e PgDn. Usare S e B per cambiare la dimensione dei caratteri.",
+
+  strings_el: {
+    "slide":"σελίδα",
+    "help?":"βοήθεια;",
+    "contents?":"περιεχόμενα;",
+    "table of contents":"πίνακας περιεχομένων",
+    "Table of Contents":"Πίνακας Περιεχομένων",
+    "restart presentation":"επανεκκίνηση παρουσίασης",
+    "restart?":"επανεκκίνηση;"
+  },
+  help_el:
+    "Πλοηγηθείτε με το κλίκ του ποντικιού, το space, τα βέλη αριστερά/δεξιά, " +
+    "ή Page Up και Page Down. Χρησιμοποιήστε τα πλήκτρα S και B για να αλλάξετε " +
+    "το μέγεθος της γραμματοσειράς.",
+
+  strings_ja: {
+    "slide":"スライド",
+    "help?":"ヘルプ",
+    "contents?":"目次",
+    "table of contents":"目次を表示",
+    "Table of Contents":"目次",
+    "restart presentation":"最初から再生",
+    "restart?":"最初から"
+  },
+  help_ja:
+     "マウス左クリック ・ スペース ・ 左右キー " +
+     "または Page Up ・ Page Downで操作， S ・ Bでフォントサイズ変更",
+
+  strings_zh: {
+    "slide":"幻灯片",
+    "help?":"帮助?",
+    "contents?":"内容?",
+    "table of contents":"目录",
+    "Table of Contents":"目录",
+    "restart presentation":"重新启动展示",
+    "restart?":"重新启动?"
+  },
+  help_zh:
+    "用鼠标点击, 空格条, 左右箭头, Pg Up 和 Pg Dn 导航. " +
+    "用 S, B 改变字体大小.",
+
+  strings_ru: {
+    "slide":"слайд",
+    "help?":"помощь?",
+    "contents?":"содержание?",
+    "table of contents":"оглавление",
+    "Table of Contents":"Оглавление",
+    "restart presentation":"перезапустить презентацию",
+    "restart?":"перезапуск?"
+  },
+  help_ru:
+    "Перемещайтесь кликая мышкой, используя клавишу пробел, стрелки" +
+    "влево/вправо или Pg Up и Pg Dn. Клавиши S и B меняют размер шрифта.",
+
+  strings_sv: {
+    "slide":"sida",
+    "help?":"hjälp",
+    "contents?":"innehåll",
+    "table of contents":"innehållsförteckning",
+    "Table of Contents":"Innehållsförteckning",
+    "restart presentation":"visa presentationen från början",
+    "restart?":"börja om"
+  },
+  help_sv:
+    "Bläddra med ett klick med vänstra musknappen, mellanslagstangenten, " +
+    "vänster- och högerpiltangenterna eller tangenterna Pg Up, Pg Dn. " +
+    "Använd tangenterna S och B för att ändra textens storlek.",
+
+  strings: { },
+
+  localize: function (src) {
+    if (src == "")
+      return src;
+
+     // try full language code, e.g. en-US
+     var s, lookup = w3c_slidy.strings[w3c_slidy.lang];
+
+     if (lookup)
+     {
+       s = lookup[src];
+
+       if (s)
+        return s;
+     }
+
+     // strip country code suffix, e.g.
+     // try en if undefined for en-US
+     var lg = w3c_slidy.lang.split("-");
+
+     if (lg.length > 1)
+     {
+       lookup = w3c_slidy.strings[lg[0]];
+
+       if (lookup)
+       {
+         s = lookup[src];
+
+         if (s)
+          return s;
+       }
+     }
+
+     // otherwise string as is
+     return src;
+  },
+
+  init_localization: function () {
+    var i18n = w3c_slidy;
+    var help_text = w3c_slidy.help_text;
+
+    // each such language array is declared in the localize array
+    // this is used as in  w3c_slidy.localize("foo");
+    this.strings = {
+      "es":this.strings_es,
+      "ca":this.strings_ca,
+      "cs":this.strings_cs,
+      "nl":this.strings_nl,
+      "de":this.strings_de,
+      "pl":this.strings_pl,
+      "fr":this.strings_fr,
+      "hu":this.strings_hu,
+      "it":this.strings_it,
+      "el":this.strings_el,
+      "jp":this.strings_ja,
+      "zh":this.strings_zh,
+      "ru":this.strings_ru,
+      "sv":this.strings_sv
+    },
+
+    i18n.strings_es[help_text] = i18n.help_es;
+    i18n.strings_ca[help_text] = i18n.help_ca;
+    i18n.strings_cs[help_text] = i18n.help_cs;
+    i18n.strings_nl[help_text] = i18n.help_nl;
+    i18n.strings_de[help_text] = i18n.help_de;
+    i18n.strings_pl[help_text] = i18n.help_pl;
+    i18n.strings_fr[help_text] = i18n.help_fr;
+    i18n.strings_hu[help_text] = i18n.help_hu;
+    i18n.strings_it[help_text] = i18n.help_it;
+    i18n.strings_el[help_text] = i18n.help_el;
+    i18n.strings_ja[help_text] = i18n.help_ja;
+    i18n.strings_zh[help_text] = i18n.help_zh;
+    i18n.strings_ru[help_text] = i18n.help_ru;
+    i18n.strings_sv[help_text] = i18n.help_sv;
+
+    w3c_slidy.lang = document.body.parentNode.getAttribute("lang");
+
+    if (!w3c_slidy.lang)
+      w3c_slidy.lang = document.body.parentNode.getAttribute("xml:lang");
+
+    if (!w3c_slidy.lang)
+      w3c_slidy.lang = "en";
+  }
+};
+
+// hack for back button behavior
+if (w3c_slidy.ie6 || w3c_slidy.ie7)
+{
+  document.write("<iframe id='historyFrame' " +
+  "src='javascript:\"<html"+"></"+"html>\"' " +
+  "height='1' width='1' " +
+  "style='position:absolute;left:-800px'></iframe>");
+}
+
+// attach event listeners for initialization
+w3c_slidy.set_up();
+
+// hide the slides as soon as body element is available
+// to reduce annoying screen mess before the onload event
+setTimeout(w3c_slidy.hide_slides, 50);
+
diff --git a/rankntypes/styles/slidy.css b/rankntypes/styles/slidy.css
new file mode 100644
index 0000000..c713c88
--- /dev/null
+++ b/rankntypes/styles/slidy.css
@@ -0,0 +1,403 @@
+/* slidy.css
+
+   Copyright (c) 2005-2010 W3C (MIT, ERCIM, Keio), All Rights Reserved.
+   W3C liability, trademark, document use and software licensing
+   rules apply, see:
+
+   http://www.w3.org/Consortium/Legal/copyright-documents
+   http://www.w3.org/Consortium/Legal/copyright-software
+*/
+body
+{
+  margin: 0 0 0 0;
+  padding: 0 0 0 0;
+  width: 100%;
+  height: 100%;
+  color: black;
+  background-color: white;
+  font-family: "Gill Sans MT", "Gill Sans", GillSans, sans-serif;
+  font-size: 14pt;
+}
+
+div.toolbar {
+  position: fixed; z-index: 200;
+  top: auto; bottom: 0; left: 0; right: 0;
+  height: 1.2em; text-align: right;
+  padding-left: 1em;
+  padding-right: 1em; 
+  font-size: 60%;
+  color: red;
+  background-color: rgb(240,240,240);
+  border-top: solid 1px rgb(180,180,180);
+}
+
+div.toolbar span.copyright {
+  color: black;
+  margin-left: 0.5em;
+}
+
+div.initial_prompt {
+  position: absolute;
+  z-index: 1000;
+  bottom: 1.2em;
+  width: 100%;
+  background-color: rgb(200,200,200);
+  opacity: 0.35;
+  background-color: rgba(200,200,200, 0.35);
+  cursor: pointer;
+}
+
+div.initial_prompt p.help {
+  text-align: center;
+}
+
+div.initial_prompt p.close {
+  text-align: right;
+  font-style: italic;
+}
+
+div.slidy_toc {
+  position: absolute;
+  z-index: 300;
+  width: 60%;
+  max-width: 30em;
+  height: 30em;
+  overflow: auto;
+  top: auto;
+  right: auto;
+  left: 4em;
+  bottom: 4em;
+  padding: 1em;
+  background: rgb(240,240,240);
+  border-style: solid;
+  border-width: 2px;
+  font-size: 60%;
+}
+
+div.slidy_toc .toc_heading {
+  text-align: center;
+  width: 100%;
+  margin: 0;
+  margin-bottom: 1em;
+  border-bottom-style: solid;
+  border-bottom-color: rgb(180,180,180);
+  border-bottom-width: 1px;
+}
+
+div.slide {
+  z-index: 20;
+  margin: 0 0 0 0;
+  padding-top: 0;
+  padding-bottom: 0;
+  padding-left: 20px;
+  padding-right: 20px;
+  border-width: 0;
+  clear: both;
+  top: 0;
+  bottom: 0;
+  left: 0;
+  right: 0;
+  line-height: 120%;
+  background-color: transparent;
+}
+
+div.background {
+  display: none;
+}
+
+div.handout {
+  margin-left: 20px;
+  margin-right: 20px;
+}
+
+div.slide.titlepage {
+  text-align: center;
+}
+
+div.slide.titlepage h1 {
+  padding-top: 10%;
+  margin-right: 0;
+}
+
+div.slide h1 {
+  padding-left: 0;
+  padding-right: 20pt;
+  padding-top: 4pt;
+  padding-bottom: 4pt;
+  margin-top: 0;
+  margin-left: 0;
+  margin-right: 60pt;
+  margin-bottom: 0.5em;
+  display: block; 
+  font-size: 160%;
+  line-height: 1.2em;
+  background: transparent;
+}
+
+@media screen and (max-device-width: 1024px)
+{
+  div.slide { font-size: 100%; }
+}
+
+@media screen and (max-device-width: 800px)
+{
+  div.slide { font-size: 200%; }
+  div.slidy_toc {
+    top: 1em;
+    left: 1em;
+    right: auto;
+    width: 80%;
+    font-size: 180%;
+  }
+}
+
+div.toc-heading {
+  width: 100%;
+  border-bottom: solid 1px rgb(180,180,180);
+  margin-bottom: 1em;
+  text-align: center;
+}
+
+img {
+  image-rendering: optimize-quality;
+}
+
+pre {
+ font-size: 80%;
+ font-weight: bold;
+ line-height: 120%;
+ padding-top: 0.2em;
+ padding-bottom: 0.2em;
+ padding-left: 1em;
+ padding-right: 1em;
+ border-style: solid;
+ border-left-width: 1em;
+ border-top-width: thin;
+ border-right-width: thin;
+ border-bottom-width: thin;
+ border-color: #95ABD0;
+ color: #00428C;
+ background-color: #E4E5E7;
+}
+
+li pre { margin-left: 0; }
+
+blockquote { font-style: italic }
+
+img { background-color: transparent }
+
+p.copyright { font-size: smaller }
+
+.center { text-align: center }
+.footnote { font-size: smaller; margin-left: 2em; }
+
+a img { border-width: 0; border-style: none }
+
+a:visited { color: navy }
+a:link { color: navy }
+a:hover { color: red; text-decoration: underline }
+a:active { color: red; text-decoration: underline }
+
+a {text-decoration: none}
+.toolbar a:link {color: blue}
+.toolbar a:visited {color: blue}
+.toolbar a:active {color: red}
+.toolbar a:hover {color: red}
+
+ul { list-style-type: square; }
+ul ul { list-style-type: disc; }
+ul ul ul { list-style-type: circle; }
+ul ul ul ul { list-style-type: disc; }
+li { margin-left: 0.5em; margin-top: 0.5em; }
+li li { font-size: 85%; font-style: italic }
+li li li { font-size: 85%; font-style: normal }
+
+div dt
+{
+  margin-left: 0;
+  margin-top: 1em;
+  margin-bottom: 0.5em;
+  font-weight: bold;
+}
+div dd
+{
+  margin-left: 2em;
+  margin-bottom: 0.5em;
+}
+
+
+p,pre,ul,ol,blockquote,h2,h3,h4,h5,h6,dl,table {
+  margin-left: 1em;
+  margin-right: 1em;
+}
+
+p.subhead { font-weight: bold; margin-top: 2em; }
+
+.smaller { font-size: smaller }
+.bigger { font-size: 130% }
+
+td,th { padding: 0.2em }
+
+ul {
+  margin: 0.5em 1.5em 0.5em 1.5em;
+  padding: 0;
+}
+
+ol {
+  margin: 0.5em 1.5em 0.5em 1.5em;
+  padding: 0;
+}
+
+ul { list-style-type: square; }
+ul ul { list-style-type: disc; }
+ul ul ul { list-style-type: circle; }
+ul ul ul ul { list-style-type: disc; }
+
+ul li { 
+  list-style: square;
+  margin: 0.1em 0em 0.6em 0;
+  padding: 0 0 0 0;
+  line-height: 140%;
+}
+
+ol li { 
+  margin: 0.1em 0em 0.6em 1.5em;
+  padding: 0 0 0 0px;
+  line-height: 140%;
+  list-style-type: decimal;
+}
+
+li ul li { 
+  font-size: 85%; 
+  font-style: italic;
+  list-style-type: disc;
+  background: transparent;
+  padding: 0 0 0 0;
+}
+li li ul li { 
+  font-size: 85%; 
+  font-style: normal;
+  list-style-type: circle;
+  background: transparent;
+  padding: 0 0 0 0;
+}
+li li li ul li {
+  list-style-type: disc;
+  background: transparent;
+  padding: 0 0 0 0;
+}
+
+li ol li {
+  list-style-type: decimal;
+}
+
+
+li li ol li {
+  list-style-type: decimal;
+}
+
+/*
+ setting class="outline on ol or ul makes it behave as an
+ ouline list where blocklevel content in li elements is
+ hidden by default and can be expanded or collapsed with
+ mouse click. Set class="expand" on li to override default
+*/
+
+ol.outline li:hover { cursor: pointer }
+ol.outline li.nofold:hover { cursor: default }
+
+ul.outline li:hover { cursor: pointer }
+ul.outline li.nofold:hover { cursor: default }
+
+ol.outline { list-style:decimal; }
+ol.outline ol { list-style-type:lower-alpha }
+
+ol.outline li.nofold {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/nofold-dim.gif) no-repeat 0px 0.5em;
+}
+ol.outline li.unfolded {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/fold-dim.gif) no-repeat 0px 0.5em;
+}
+ol.outline li.folded {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/unfold-dim.gif) no-repeat 0px 0.5em;
+}
+ol.outline li.unfolded:hover {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/fold.gif) no-repeat 0px 0.5em;
+}
+ol.outline li.folded:hover {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/unfold.gif) no-repeat 0px 0.5em;
+}
+
+ul.outline li.nofold {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/nofold-dim.gif) no-repeat 0px 0.5em;
+}
+ul.outline li.unfolded {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/fold-dim.gif) no-repeat 0px 0.5em;
+}
+ul.outline li.folded {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/unfold-dim.gif) no-repeat 0px 0.5em;
+}
+ul.outline li.unfolded:hover {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/fold.gif) no-repeat 0px 0.5em;
+}
+ul.outline li.folded:hover {
+  padding: 0 0 0 20px;
+  background: transparent url(../graphics/unfold.gif) no-repeat 0px 0.5em;
+}
+
+/* for slides with class "title" in table of contents */
+a.titleslide { font-weight: bold; font-style: italic }
+
+/*
+ hide images for work around for save as bug
+ where browsers fail to save images used by CSS
+*/
+img.hidden { display: none; visibility: hidden }
+div.initial_prompt { display: none; visibility: hidden }
+
+  div.slide {
+     visibility: visible;
+     position: inherit;
+  }
+  div.handout {
+     border-top-style: solid;
+     border-top-width: thin;
+     border-top-color: black;
+  }
+
+@media screen {
+  .hidden { display: none; visibility: visible }
+
+  div.slide.hidden { display: block; visibility: visible }
+  div.handout.hidden { display: block; visibility: visible }
+  div.background { display: none; visibility: hidden }
+  body.single_slide div.initial_prompt { display: block; visibility: visible }
+  body.single_slide div.background { display: block; visibility: visible }
+  body.single_slide div.background.hidden { display: none; visibility: hidden }
+  body.single_slide .invisible { visibility: hidden }
+  body.single_slide .hidden { display: none; visibility: hidden }
+  body.single_slide div.slide { position: absolute }
+  body.single_slide div.handout { display: none; visibility: hidden }
+}
+
+@media print {
+  .hidden { display: block; visibility: visible }
+
+  div.slide pre { font-size: 60%; padding-left: 0.5em; }
+  div.toolbar { display: none; visibility: hidden; }
+  div.slidy_toc { display: none; visibility: hidden; }
+  div.background { display: none; visibility: hidden; }
+  div.slide { page-break-before: always }
+  /* :first-child isn't reliable for print media */
+  div.slide.first-slide { page-break-before: avoid }
+}
+