From 4c4a0e0f3fe9b4e33f2182f3f8e20d87736b371d Mon Sep 17 00:00:00 2001
From: "Cheng-Han, Wu" <jackymaxj@gmail.com>
Date: Thu, 11 Feb 2016 03:45:13 -0600
Subject: [PATCH] Fixed prevent XSS might break lots of tags and only need
 after rendered

---
 lib/response.js               |   3 -
 package.json                  |   3 +-
 public/js/extra.js            |  22 +-
 public/js/index.js            |   5 +-
 public/js/pretty.js           |   4 +-
 public/js/render.js           |  13 ++
 public/js/reveal-markdown.js  | 405 ++++++++++++++++++++++++++++++++++
 public/views/foot.ejs         |   1 +
 public/views/pretty.ejs       |   2 +
 public/views/slide/reveal.hbs |   4 +-
 10 files changed, 442 insertions(+), 20 deletions(-)
 create mode 100644 public/js/render.js
 create mode 100755 public/js/reveal-markdown.js

diff --git a/lib/response.js b/lib/response.js
index c12c4caa..07cb5ba9 100644
--- a/lib/response.js
+++ b/lib/response.js
@@ -11,7 +11,6 @@ var shortId = require('shortid');
 var metaMarked = require('meta-marked');
 var querystring = require('querystring');
 var request = require('request');
-var xss = require('xss');
 
 //core
 var config = require("../config.js");
@@ -228,7 +227,6 @@ function showPublishNote(req, res, next) {
                         //na
                     }
                     var updatetime = notedata.update_time;
-                    body = xss(body); // prevent xss
                     var text = S(body).escapeHTML().s;
                     var title = notedata.title;
                     var decodedTitle = LZString.decompressFromBase64(title);
@@ -612,7 +610,6 @@ function showPublishSlide(req, res, next) {
                     var decodedTitle = LZString.decompressFromBase64(title);
                     if (decodedTitle) title = decodedTitle;
                     title = Note.generateWebTitle(title);
-                    body = xss(body); // prevent xss
                     var text = S(body).escapeHTML().s;
                     render(res, title, text);
                 });
diff --git a/package.json b/package.json
index d96fabc7..4d701966 100644
--- a/package.json
+++ b/package.json
@@ -49,8 +49,7 @@
     "socket.io": "1.4.4",
     "string": "^3.3.1",
     "toobusy-js": "^0.4.2",
-    "winston": "^2.1.1",
-    "xss": "^0.2.10"
+    "winston": "^2.1.1"
   },
   "engines": {
     "node": ">=4.x"
diff --git a/public/js/extra.js b/public/js/extra.js
index 2c9c9037..a2ae83f6 100644
--- a/public/js/extra.js
+++ b/public/js/extra.js
@@ -180,7 +180,7 @@ function finishView(view) {
         .each(function (key, value) {
             $.ajax({
                 type: 'GET',
-                url: '//vimeo.com/api/v2/video/' + $(value).attr('videoid') + '.json',
+                url: '//vimeo.com/api/v2/video/' + $(value).attr('data-videoid') + '.json',
                 jsonp: 'callback',
                 dataType: 'jsonp',
                 success: function (data) {
@@ -285,7 +285,7 @@ function finishView(view) {
         .each(function (key, value) {
             $.ajax({
                 type: 'GET',
-                url: '//www.slideshare.net/api/oembed/2?url=http://www.slideshare.net/' + $(value).attr('slideshareid') + '&format=json',
+                url: '//www.slideshare.net/api/oembed/2?url=http://www.slideshare.net/' + $(value).attr('data-slideshareid') + '&format=json',
                 jsonp: 'callback',
                 dataType: 'jsonp',
                 success: function (data) {
@@ -304,7 +304,7 @@ function finishView(view) {
     //speakerdeck
     view.find(".speakerdeck.raw").removeClass("raw")
         .each(function (key, value) {
-            var url = 'https://speakerdeck.com/oembed.json?url=https%3A%2F%2Fspeakerdeck.com%2F' + encodeURIComponent($(value).attr('speakerdeckid'));
+            var url = 'https://speakerdeck.com/oembed.json?url=https%3A%2F%2Fspeakerdeck.com%2F' + encodeURIComponent($(value).attr('data-speakerdeckid'));
             //use yql because speakerdeck not support jsonp
             $.ajax({
                 url: 'https://query.yahooapis.com/v1/public/yql',
@@ -383,8 +383,8 @@ function exportToHTML(view) {
         $(value).attr('src', 'https://www.tortue.me/emoji/' + name + '.png');
     });
     //replace video to iframe
-    src.find("div[videoid]").each(function (key, value) {
-        var id = $(value).attr('videoid');
+    src.find("div[data-videoid]").each(function (key, value) {
+        var id = $(value).attr('data-videoid');
         var style = $(value).attr('style');
         var url = null;
         if ($(value).hasClass('youtube')) {
@@ -534,9 +534,9 @@ function smoothHashScroll() {
 }
 
 function imgPlayiframe(element, src) {
-    if (!$(element).attr("videoid")) return;
+    if (!$(element).attr("data-videoid")) return;
     var iframe = $("<iframe frameborder='0' webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>");
-    $(iframe).attr("src", src + $(element).attr("videoid") + '?autoplay=1');
+    $(iframe).attr("src", src + $(element).attr("data-videoid") + '?autoplay=1');
     $(element).find('img').css('visibility', 'hidden');
     $(element).append(iframe);
 }
@@ -730,7 +730,7 @@ var youtubePlugin = new Plugin(
         var videoid = match[1];
         if (!videoid) return;
         var div = $('<div class="youtube raw"></div>');
-        div.attr('videoid', videoid);
+        div.attr('data-videoid', videoid);
         var thumbnail_src = '//img.youtube.com/vi/' + videoid + '/hqdefault.jpg';
         var image = '<img src="' + thumbnail_src + '" />';
         div.append(image);
@@ -749,7 +749,7 @@ var vimeoPlugin = new Plugin(
         var videoid = match[1];
         if (!videoid) return;
         var div = $('<div class="vimeo raw"></div>');
-        div.attr('videoid', videoid);
+        div.attr('data-videoid', videoid);
         var icon = '<i class="icon fa fa-vimeo-square fa-5x"></i>';
         div.append(icon);
         return div[0].outerHTML;
@@ -799,7 +799,7 @@ var slidesharePlugin = new Plugin(
     function (match, utils) {
         var slideshareid = match[1];
         var div = $('<div class="slideshare raw"></div>');
-        div.attr('slideshareid', slideshareid);
+        div.attr('data-slideshareid', slideshareid);
         return div[0].outerHTML;
     }
 );
@@ -812,7 +812,7 @@ var speakerdeckPlugin = new Plugin(
     function (match, utils) {
         var speakerdeckid = match[1];
         var div = $('<div class="speakerdeck raw"></div>');
-        div.attr('speakerdeckid', speakerdeckid);
+        div.attr('data-speakerdeckid', speakerdeckid);
         return div[0].outerHTML;
     }
 );
diff --git a/public/js/index.js b/public/js/index.js
index 1150f7ae..2e797ac3 100644
--- a/public/js/index.js
+++ b/public/js/index.js
@@ -2132,11 +2132,12 @@ var lastResult = null;
 function updateViewInner() {
     if (currentMode == modeType.edit || !isDirty) return;
     var value = editor.getValue();
-    value = filterXSS(value); // prevent xss
     md.meta = {};
     md.render(value); //only for get meta
     parseMeta(md, ui.area.markdown, $('#toc'), $('#toc-affix'));
-    var result = postProcess(md.render(value)).children().toArray();
+    var rendered = md.render(value);
+    rendered = preventXSS(rendered);
+    var result = postProcess(rendered).children().toArray();
     partialUpdate(result, lastResult, ui.area.markdown.children().toArray());
     if (result && lastResult && result.length != lastResult.length)
         updateDataAttrs(result, ui.area.markdown.children().toArray());
diff --git a/public/js/pretty.js b/public/js/pretty.js
index 43e833c2..a38dc244 100644
--- a/public/js/pretty.js
+++ b/public/js/pretty.js
@@ -3,7 +3,9 @@ var text = $('<textarea/>').html(markdown.html()).text();
 md.meta = {};
 md.render(text); //only for get meta
 parseMeta(md, markdown, $('#toc'), $('#toc-affix'));
-var result = postProcess(md.render(text));
+var rendered = md.render(text);
+rendered = preventXSS(rendered);
+var result = postProcess(rendered);
 markdown.html(result.html());
 $(document.body).show();
 finishView(markdown);
diff --git a/public/js/render.js b/public/js/render.js
new file mode 100644
index 00000000..1abb68c5
--- /dev/null
+++ b/public/js/render.js
@@ -0,0 +1,13 @@
+function preventXSS(html) {
+    var options = {
+        allowCommentTag: true,
+        onIgnoreTagAttr: function (tag, name, value, isWhiteAttr) {
+            // allow attr start with 'data-' or equal 'id' and 'class'
+            if (name.substr(0, 5) === 'data-' || name === 'id' || name === 'class') {
+                // escape its value using built-in escapeAttrValue function
+                return name + '="' + filterXSS.escapeAttrValue(value) + '"';
+            }
+        }
+    };
+    return filterXSS(html, options);
+}
\ No newline at end of file
diff --git a/public/js/reveal-markdown.js b/public/js/reveal-markdown.js
new file mode 100755
index 00000000..a3f2505a
--- /dev/null
+++ b/public/js/reveal-markdown.js
@@ -0,0 +1,405 @@
+/**
+ * The reveal.js markdown plugin. Handles parsing of
+ * markdown inside of presentations as well as loading
+ * of external markdown documents.
+ */
+(function( root, factory ) {
+	if( typeof exports === 'object' ) {
+		module.exports = factory( require( './marked' ) );
+	}
+	else {
+		// Browser globals (root is window)
+		root.RevealMarkdown = factory( root.marked );
+		root.RevealMarkdown.initialize();
+	}
+}( this, function( marked ) {
+
+	if( typeof marked === 'undefined' ) {
+		throw 'The reveal.js Markdown plugin requires marked to be loaded';
+	}
+
+	if( typeof hljs !== 'undefined' ) {
+		marked.setOptions({
+			highlight: function( lang, code ) {
+				return hljs.highlightAuto( lang, code ).value;
+			}
+		});
+	}
+
+	var DEFAULT_SLIDE_SEPARATOR = '^\r?\n---\r?\n$',
+		DEFAULT_NOTES_SEPARATOR = 'note:',
+		DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR = '\\\.element\\\s*?(.+?)$',
+		DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR = '\\\.slide:\\\s*?(\\\S.+?)$';
+
+	var SCRIPT_END_PLACEHOLDER = '__SCRIPT_END__';
+
+
+	/**
+	 * Retrieves the markdown contents of a slide section
+	 * element. Normalizes leading tabs/whitespace.
+	 */
+	function getMarkdownFromSlide( section ) {
+
+		var template = section.querySelector( 'script' );
+
+		// strip leading whitespace so it isn't evaluated as code
+		var text = ( template || section ).textContent;
+
+		// restore script end tags
+		text = text.replace( new RegExp( SCRIPT_END_PLACEHOLDER, 'g' ), '</script>' );
+
+		var leadingWs = text.match( /^\n?(\s*)/ )[1].length,
+			leadingTabs = text.match( /^\n?(\t*)/ )[1].length;
+
+		if( leadingTabs > 0 ) {
+			text = text.replace( new RegExp('\\n?\\t{' + leadingTabs + '}','g'), '\n' );
+		}
+		else if( leadingWs > 1 ) {
+			text = text.replace( new RegExp('\\n? {' + leadingWs + '}', 'g'), '\n' );
+		}
+
+		return text;
+
+	}
+
+	/**
+	 * Given a markdown slide section element, this will
+	 * return all arguments that aren't related to markdown
+	 * parsing. Used to forward any other user-defined arguments
+	 * to the output markdown slide.
+	 */
+	function getForwardedAttributes( section ) {
+
+		var attributes = section.attributes;
+		var result = [];
+
+		for( var i = 0, len = attributes.length; i < len; i++ ) {
+			var name = attributes[i].name,
+				value = attributes[i].value;
+
+			// disregard attributes that are used for markdown loading/parsing
+			if( /data\-(markdown|separator|vertical|notes)/gi.test( name ) ) continue;
+
+			if( value ) {
+				result.push( name + '="' + value + '"' );
+			}
+			else {
+				result.push( name );
+			}
+		}
+
+		return result.join( ' ' );
+
+	}
+
+	/**
+	 * Inspects the given options and fills out default
+	 * values for what's not defined.
+	 */
+	function getSlidifyOptions( options ) {
+
+		options = options || {};
+		options.separator = options.separator || DEFAULT_SLIDE_SEPARATOR;
+		options.notesSeparator = options.notesSeparator || DEFAULT_NOTES_SEPARATOR;
+		options.attributes = options.attributes || '';
+
+		return options;
+
+	}
+
+	/**
+	 * Helper function for constructing a markdown slide.
+	 */
+	function createMarkdownSlide( content, options ) {
+
+		options = getSlidifyOptions( options );
+
+		var notesMatch = content.split( new RegExp( options.notesSeparator, 'mgi' ) );
+
+		if( notesMatch.length === 2 ) {
+			content = notesMatch[0] + '<aside class="notes" data-markdown>' + notesMatch[1].trim() + '</aside>';
+		}
+
+		// prevent script end tags in the content from interfering
+		// with parsing
+		content = content.replace( /<\/script>/g, SCRIPT_END_PLACEHOLDER );
+
+		return '<script type="text/template">' + content + '</script>';
+
+	}
+
+	/**
+	 * Parses a data string into multiple slides based
+	 * on the passed in separator arguments.
+	 */
+	function slidify( markdown, options ) {
+
+		options = getSlidifyOptions( options );
+
+		var separatorRegex = new RegExp( options.separator + ( options.verticalSeparator ? '|' + options.verticalSeparator : '' ), 'mg' ),
+			horizontalSeparatorRegex = new RegExp( options.separator );
+
+		var matches,
+			lastIndex = 0,
+			isHorizontal,
+			wasHorizontal = true,
+			content,
+			sectionStack = [];
+
+		// iterate until all blocks between separators are stacked up
+		while( matches = separatorRegex.exec( markdown ) ) {
+			notes = null;
+
+			// determine direction (horizontal by default)
+			isHorizontal = horizontalSeparatorRegex.test( matches[0] );
+
+			if( !isHorizontal && wasHorizontal ) {
+				// create vertical stack
+				sectionStack.push( [] );
+			}
+
+			// pluck slide content from markdown input
+			content = markdown.substring( lastIndex, matches.index );
+
+			if( isHorizontal && wasHorizontal ) {
+				// add to horizontal stack
+				sectionStack.push( content );
+			}
+			else {
+				// add to vertical stack
+				sectionStack[sectionStack.length-1].push( content );
+			}
+
+			lastIndex = separatorRegex.lastIndex;
+			wasHorizontal = isHorizontal;
+		}
+
+		// add the remaining slide
+		( wasHorizontal ? sectionStack : sectionStack[sectionStack.length-1] ).push( markdown.substring( lastIndex ) );
+
+		var markdownSections = '';
+
+		// flatten the hierarchical stack, and insert <section data-markdown> tags
+		for( var i = 0, len = sectionStack.length; i < len; i++ ) {
+			// vertical
+			if( sectionStack[i] instanceof Array ) {
+				markdownSections += '<section '+ options.attributes +'>';
+
+				sectionStack[i].forEach( function( child ) {
+					markdownSections += '<section data-markdown>' +  createMarkdownSlide( child, options ) + '</section>';
+				} );
+
+				markdownSections += '</section>';
+			}
+			else {
+				markdownSections += '<section '+ options.attributes +' data-markdown>' + createMarkdownSlide( sectionStack[i], options ) + '</section>';
+			}
+		}
+
+		return markdownSections;
+
+	}
+
+	/**
+	 * Parses any current data-markdown slides, splits
+	 * multi-slide markdown into separate sections and
+	 * handles loading of external markdown.
+	 */
+	function processSlides() {
+
+		var sections = document.querySelectorAll( '[data-markdown]'),
+			section;
+
+		for( var i = 0, len = sections.length; i < len; i++ ) {
+
+			section = sections[i];
+
+			if( section.getAttribute( 'data-markdown' ).length ) {
+
+				var xhr = new XMLHttpRequest(),
+					url = section.getAttribute( 'data-markdown' );
+
+				datacharset = section.getAttribute( 'data-charset' );
+
+				// see https://developer.mozilla.org/en-US/docs/Web/API/element.getAttribute#Notes
+				if( datacharset != null && datacharset != '' ) {
+					xhr.overrideMimeType( 'text/html; charset=' + datacharset );
+				}
+
+				xhr.onreadystatechange = function() {
+					if( xhr.readyState === 4 ) {
+						// file protocol yields status code 0 (useful for local debug, mobile applications etc.)
+						if ( ( xhr.status >= 200 && xhr.status < 300 ) || xhr.status === 0 ) {
+
+							section.outerHTML = slidify( xhr.responseText, {
+								separator: section.getAttribute( 'data-separator' ),
+								verticalSeparator: section.getAttribute( 'data-separator-vertical' ),
+								notesSeparator: section.getAttribute( 'data-separator-notes' ),
+								attributes: getForwardedAttributes( section )
+							});
+
+						}
+						else {
+
+							section.outerHTML = '<section data-state="alert">' +
+								'ERROR: The attempt to fetch ' + url + ' failed with HTTP status ' + xhr.status + '.' +
+								'Check your browser\'s JavaScript console for more details.' +
+								'<p>Remember that you need to serve the presentation HTML from a HTTP server.</p>' +
+								'</section>';
+
+						}
+					}
+				};
+
+				xhr.open( 'GET', url, false );
+
+				try {
+					xhr.send();
+				}
+				catch ( e ) {
+					alert( 'Failed to get the Markdown file ' + url + '. Make sure that the presentation and the file are served by a HTTP server and the file can be found there. ' + e );
+				}
+
+			}
+			else if( section.getAttribute( 'data-separator' ) || section.getAttribute( 'data-separator-vertical' ) || section.getAttribute( 'data-separator-notes' ) ) {
+
+				section.outerHTML = slidify( getMarkdownFromSlide( section ), {
+					separator: section.getAttribute( 'data-separator' ),
+					verticalSeparator: section.getAttribute( 'data-separator-vertical' ),
+					notesSeparator: section.getAttribute( 'data-separator-notes' ),
+					attributes: getForwardedAttributes( section )
+				});
+
+			}
+			else {
+				section.innerHTML = createMarkdownSlide( getMarkdownFromSlide( section ) );
+			}
+		}
+
+	}
+
+	/**
+	 * Check if a node value has the attributes pattern.
+	 * If yes, extract it and add that value as one or several attributes
+	 * the the terget element.
+	 *
+	 * You need Cache Killer on Chrome to see the effect on any FOM transformation
+	 * directly on refresh (F5)
+	 * http://stackoverflow.com/questions/5690269/disabling-chrome-cache-for-website-development/7000899#answer-11786277
+	 */
+	function addAttributeInElement( node, elementTarget, separator ) {
+
+		var mardownClassesInElementsRegex = new RegExp( separator, 'mg' );
+		var mardownClassRegex = new RegExp( "([^\"= ]+?)=\"([^\"=]+?)\"", 'mg' );
+		var nodeValue = node.nodeValue;
+		if( matches = mardownClassesInElementsRegex.exec( nodeValue ) ) {
+
+			var classes = matches[1];
+			nodeValue = nodeValue.substring( 0, matches.index ) + nodeValue.substring( mardownClassesInElementsRegex.lastIndex );
+			node.nodeValue = nodeValue;
+			while( matchesClass = mardownClassRegex.exec( classes ) ) {
+				elementTarget.setAttribute( matchesClass[1], matchesClass[2] );
+			}
+			return true;
+		}
+		return false;
+	}
+
+	/**
+	 * Add attributes to the parent element of a text node,
+	 * or the element of an attribute node.
+	 */
+	function addAttributes( section, element, previousElement, separatorElementAttributes, separatorSectionAttributes ) {
+
+		if ( element != null && element.childNodes != undefined && element.childNodes.length > 0 ) {
+			previousParentElement = element;
+			for( var i = 0; i < element.childNodes.length; i++ ) {
+				childElement = element.childNodes[i];
+				if ( i > 0 ) {
+					j = i - 1;
+					while ( j >= 0 ) {
+						aPreviousChildElement = element.childNodes[j];
+						if ( typeof aPreviousChildElement.setAttribute == 'function' && aPreviousChildElement.tagName != "BR" ) {
+							previousParentElement = aPreviousChildElement;
+							break;
+						}
+						j = j - 1;
+					}
+				}
+				parentSection = section;
+				if( childElement.nodeName ==  "section" ) {
+					parentSection = childElement ;
+					previousParentElement = childElement ;
+				}
+				if ( typeof childElement.setAttribute == 'function' || childElement.nodeType == Node.COMMENT_NODE ) {
+					addAttributes( parentSection, childElement, previousParentElement, separatorElementAttributes, separatorSectionAttributes );
+				}
+			}
+		}
+
+		if ( element.nodeType == Node.COMMENT_NODE ) {
+			if ( addAttributeInElement( element, previousElement, separatorElementAttributes ) == false ) {
+				addAttributeInElement( element, section, separatorSectionAttributes );
+			}
+		}
+	}
+
+	/**
+	 * Converts any current data-markdown slides in the
+	 * DOM to HTML.
+	 */
+	function convertSlides() {
+
+		var sections = document.querySelectorAll( '[data-markdown]');
+
+		for( var i = 0, len = sections.length; i < len; i++ ) {
+
+			var section = sections[i];
+
+			// Only parse the same slide once
+			if( !section.getAttribute( 'data-markdown-parsed' ) ) {
+
+				section.setAttribute( 'data-markdown-parsed', true )
+
+				var notes = section.querySelector( 'aside.notes' );
+				var markdown = getMarkdownFromSlide( section );
+
+                var rendered = marked( markdown );
+                rendered = preventXSS(rendered);
+                
+				section.innerHTML = rendered;
+				addAttributes( 	section, section, null, section.getAttribute( 'data-element-attributes' ) ||
+								section.parentNode.getAttribute( 'data-element-attributes' ) ||
+								DEFAULT_ELEMENT_ATTRIBUTES_SEPARATOR,
+								section.getAttribute( 'data-attributes' ) ||
+								section.parentNode.getAttribute( 'data-attributes' ) ||
+								DEFAULT_SLIDE_ATTRIBUTES_SEPARATOR);
+
+				// If there were notes, we need to re-add them after
+				// having overwritten the section's HTML
+				if( notes ) {
+					section.appendChild( notes );
+				}
+
+			}
+
+		}
+
+	}
+
+	// API
+	return {
+
+		initialize: function() {
+			processSlides();
+			convertSlides();
+		},
+
+		// TODO: Do these belong in the API?
+		processSlides: processSlides,
+		convertSlides: convertSlides,
+		slidify: slidify
+
+	};
+
+}));
diff --git a/public/views/foot.ejs b/public/views/foot.ejs
index 3a5ef145..dfb07ece 100644
--- a/public/views/foot.ejs
+++ b/public/views/foot.ejs
@@ -60,6 +60,7 @@
 <script type="text/javascript" src="//cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" defer></script>
 <script src="/js/common.js" defer></script>
 <script src="/js/extra.js" defer></script>
+<script src="/js/render.js" defer></script>
 <script src="/js/history.js" defer></script>
 <script src="/js/index.js" defer></script>
 <script src="/js/syncscroll.js" defer></script>
\ No newline at end of file
diff --git a/public/views/pretty.ejs b/public/views/pretty.ejs
index 07b0f7b2..998b2ef7 100644
--- a/public/views/pretty.ejs
+++ b/public/views/pretty.ejs
@@ -76,6 +76,7 @@
 <script src="<%- url %>/vendor/js-yaml/dist/js-yaml.min.js" defer></script>
 <% } %>
 <script src="<%- url %>/vendor/lz-string/libs/lz-string.min.js" defer></script>
+<script src="<%- url %>/vendor/xss/dist/xss.min.js" defer></script>
 <script src="<%- url %>/vendor/remarkable.min.js" defer></script>
 <script src="<%- url %>/vendor/remarkable-regex.js" defer></script>
 <script src="<%- url %>/vendor/gist-embed.js" defer></script>
@@ -94,4 +95,5 @@
 </script>
 <script type="text/javascript" src="//cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" defer></script>
 <script src="<%- url %>/js/extra.js" defer></script>
+<script src="<%- url %>/js/render.js" defer></script>
 <script src="<%- url %>/js/pretty.js" defer></script>
\ No newline at end of file
diff --git a/public/views/slide/reveal.hbs b/public/views/slide/reveal.hbs
index fd19f23c..fd87ddb3 100644
--- a/public/views/slide/reveal.hbs
+++ b/public/views/slide/reveal.hbs
@@ -31,6 +31,8 @@
         <script src="/vendor/reveal.js/lib/js/head.min.js"></script>
         <script src="/vendor/reveal.js/js/reveal.js"></script>
         <script src="/vendor/string.min.js"></script>
+        <script src="/vendor/xss/dist/xss.min.js"></script>
+        <script src="/js/render.js"></script>
 
         <script>
             var body = $(".slides").html();
@@ -53,7 +55,7 @@
             var deps = [
               { src: '/vendor/reveal.js/lib/js/classList.js', condition: function() { return !document.body.classList; } },
               { src: '/vendor/reveal.js/plugin/markdown/marked.js', condition: function() { return !!document.querySelector('[data-markdown]'); } },
-              { src: '/vendor/reveal.js/plugin/markdown/markdown.js', condition: function() { return !!document.querySelector('[data-markdown]'); } },
+              { src: '/js/reveal-markdown.js', condition: function() { return !!document.querySelector('[data-markdown]'); } },
               { src: '/vendor/reveal.js/plugin/highlight/highlight.js', async: true, callback: function() { hljs.initHighlightingOnLoad(); } },
               { src: '/vendor/reveal.js/plugin/notes/notes.js', async: true, condition: function() { return !!document.body.classList; } },
               { src: '/vendor/reveal.js/plugin/math/math.js', async: true }