Code change:
<ins> /** * marked - a markdown parser * Copyright (c) 2011-2014, Christopher Jeffrey. (MIT Licensed) * https://github.com/chjj/marked */ (function(){var block={newline:/^n+/,code:/^( {4}[^n]+n*)+/,fences:noop,hr:/^( *[-*_]){3,} *(?:n+|$)/,heading:/^ *(#{1,6}) *([^n]+?) *#* *(?:n+|$)/,nptable:noop,lheading:/^([^n]+)n *(=|-){2,} *(?:n+|$)/,blockquote:/^( *>[^n]+(n(?!def)[^n]+)*n*)+/,list:/^( *)(bull) [sS]+?(?:hr|def|n{2,}(?! )(?!1bull )n*|s*$)/,html:/^ *(?:comment|closed|closing) *(?:n{2,}|s*$)/,def:/^ *[([^]]+)]: *<?([^s>]+)>?(?: +["(]([^n]+)[")])? *(?:n+|$)/,table:noop,paragraph:/^((?:[^n]+n?(?!hr|heading|lheading|blockquote|tag|def))+)n*/,text:/^[^n]+/};block.bullet=/(?:[*+-]|d+.)/;block.item=/^( *)(bull) [^n]*(?:n(?!1bull )[^n]*)*/;block.item=replace(block.item,"gm")(/bull/g,block.bullet)();block.list=replace(block.list)(/bull/g,block.bullet)("hr","n+(?=1?(?:[-*_] *){3,}(?:n+|$))")("def","n+(?="+block.def.source+")")();block.blockquote=replace(block.blockquote)("def",block.def)();block._tag="(?!(?:"+"a|em|strong|small|s|cite|q|dfn|abbr|data|time|code"+"|var|samp|kbd|sub|sup|i|b|u|mark|ruby|rt|rp|bdi|bdo"+"|span|br|wbr|ins|del|img)b)w+(?!:/|[^ws@]*@)b";block.html=replace(block.html)("comment",/<!--[sS]*?-->/)("closed",/<(tag)[sS]+?</1>/)("closing",/<tag(?:"[^"]*"|'[^']*'|[^'">])*?>/)(/tag/g,block._tag)();block.paragraph=replace(block.paragraph)("hr",block.hr)("heading",block.heading)("lheading",block.lheading)("blockquote",block.blockquote)("tag","<"+block._tag)("def",block.def)();block.normal=merge({},block);block.gfm=merge({},block.normal,{fences:/^ *(`{3,}|~{3,}) *(S+)? *n([sS]+?)s*1 *(?:n+|$)/,paragraph:/^/});block.gfm.paragraph=replace(block.paragraph)("(?!","(?!"+block.gfm.fences.source.replace("1","2")+"|"+block.list.source.replace("1","3")+"|")();block.tables=merge({},block.gfm,{nptable:/^ *(S.*|.*)n *([-:]+ *|[-| :]*)n((?:.*|.*(?:n|$))*)n*/,table:/^ *|(.+)n *|( *[-:]+[-| :]*)n((?: *|.*(?:n|$))*)n*/});function Lexer(options){this.tokens=[];this.tokens.links={};this.options=options||marked.defaults;this.rules=block.normal;if(this.options.gfm){if(this.options.tables){this.rules=block.tables}else{this.rules=block.gfm}}}Lexer.rules=block;Lexer.lex=function(src,options){var lexer=new Lexer(options);return lexer.lex(src)};Lexer.prototype.lex=function(src){src=src.replace(/rn|r/g,"n").replace(/t/g,"    ").replace(/u00a0/g," ").replace(/u2424/g,"n");return this.token(src,true)};Lexer.prototype.token=function(src,top,bq){var src=src.replace(/^ +$/gm,""),next,loose,cap,bull,b,item,space,i,l;while(src){if(cap=this.rules.newline.exec(src)){src=src.substring(cap[0].length);if(cap[0].length>1){this.tokens.push({type:"space"})}}if(cap=this.rules.code.exec(src)){src=src.substring(cap[0].length);cap=cap[0].replace(/^ {4}/gm,"");this.tokens.push({type:"code",text:!this.options.pedantic?cap.replace(/n+$/,""):cap});continue}if(cap=this.rules.fences.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:"code",lang:cap[2],text:cap[3]});continue}if(cap=this.rules.heading.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:"heading",depth:cap[1].length,text:cap[2]});continue}if(top&&(cap=this.rules.nptable.exec(src))){src=src.substring(cap[0].length);item={type:"table",header:cap[1].replace(/^ *| *| *$/g,"").split(/ *| */),align:cap[2].replace(/^ *|| *$/g,"").split(/ *| */),cells:cap[3].replace(/n$/,"").split("n")};for(i=0;i<item.align.length;i++){if(/^ *-+: *$/.test(item.align[i])){item.align[i]="right"}else if(/^ *:-+: *$/.test(item.align[i])){item.align[i]="center"}else if(/^ *:-+ *$/.test(item.align[i])){item.align[i]="left"}else{item.align[i]=null}}for(i=0;i<item.cells.length;i++){item.cells[i]=item.cells[i].split(/ *| */)}this.tokens.push(item);continue}if(cap=this.rules.lheading.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:"heading",depth:cap[2]==="="?1:2,text:cap[1]});continue}if(cap=this.rules.hr.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:"hr"});continue}if(cap=this.rules.blockquote.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:"blockquote_start"});cap=cap[0].replace(/^ *> ?/gm,"");this.token(cap,top,true);this.tokens.push({type:"blockquote_end"});continue}if(cap=this.rules.list.exec(src)){src=src.substring(cap[0].length);bull=cap[2];this.tokens.push({type:"list_start",ordered:bull.length>1});cap=cap[0].match(this.rules.item);next=false;l=cap.length;i=0;for(;i<l;i++){item=cap[i];space=item.length;item=item.replace(/^ *([*+-]|d+.) +/,"");if(~item.indexOf("n ")){space-=item.length;item=!this.options.pedantic?item.replace(new RegExp("^ {1,"+space+"}","gm"),""):item.replace(/^ {1,4}/gm,"")}if(this.options.smartLists&&i!==l-1){b=block.bullet.exec(cap[i+1])[0];if(bull!==b&&!(bull.length>1&&b.length>1)){src=cap.slice(i+1).join("n")+src;i=l-1}}loose=next||/nn(?!s*$)/.test(item);if(i!==l-1){next=item.charAt(item.length-1)==="n";if(!loose)loose=next}this.tokens.push({type:loose?"loose_item_start":"list_item_start"});this.token(item,false,bq);this.tokens.push({type:"list_item_end"})}this.tokens.push({type:"list_end"});continue}if(cap=this.rules.html.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:this.options.sanitize?"paragraph":"html",pre:cap[1]==="pre"||cap[1]==="script"||cap[1]==="style",text:cap[0]});continue}if(!bq&&top&&(cap=this.rules.def.exec(src))){src=src.substring(cap[0].length);this.tokens.links[cap[1].toLowerCase()]={href:cap[2],title:cap[3]};continue}if(top&&(cap=this.rules.table.exec(src))){src=src.substring(cap[0].length);item={type:"table",header:cap[1].replace(/^ *| *| *$/g,"").split(/ *| */),align:cap[2].replace(/^ *|| *$/g,"").split(/ *| */),cells:cap[3].replace(/(?: *| *)?n$/,"").split("n")};for(i=0;i<item.align.length;i++){if(/^ *-+: *$/.test(item.align[i])){item.align[i]="right"}else if(/^ *:-+: *$/.test(item.align[i])){item.align[i]="center"}else if(/^ *:-+ *$/.test(item.align[i])){item.align[i]="left"}else{item.align[i]=null}}for(i=0;i<item.cells.length;i++){item.cells[i]=item.cells[i].replace(/^ *| *| *| *$/g,"").split(/ *| */)}this.tokens.push(item);continue}if(top&&(cap=this.rules.paragraph.exec(src))){src=src.substring(cap[0].length);this.tokens.push({type:"paragraph",text:cap[1].charAt(cap[1].length-1)==="n"?cap[1].slice(0,-1):cap[1]});continue}if(cap=this.rules.text.exec(src)){src=src.substring(cap[0].length);this.tokens.push({type:"text",text:cap[0]});continue}if(src){throw new Error("Infinite loop on byte: "+src.charCodeAt(0))}}return this.tokens};var inline={escape:/^([`*{}[]()#+-.!_>])/,autolink:/^<([^ >]+(@|:/)[^ >]+)>/,url:noop,tag:/^<!--[sS]*?-->|^</?w+(?:"[^"]*"|'[^']*'|[^'">])*?>/,link:/^!?[(inside)](href)/,reflink:/^!?[(inside)]s*[([^]]*)]/,nolink:/^!?[((?:[[^]]*]|[^[]])*)]/,strong:/^__([sS]+?)__(?!_)|^**([sS]+?)**(?!*)/,em:/^b_((?:__|[sS])+?)_b|^*((?:**|[sS])+?)*(?!*)/,code:/^(`+)s*([sS]*?[^`])s*1(?!`)/,br:/^ {2,}n(?!s*$)/,del:noop,text:/^[sS]+?(?=[<![_*`]| {2,}n|$)/};inline._inside=/(?:[[^]]*]|[^[]]|](?=[^[]*]))*/;inline._href=/s*<?([sS]*?)>?(?:s+['"]([sS]*?)['"])?s*/;inline.link=replace(inline.link)("inside",inline._inside)("href",inline._href)();inline.reflink=replace(inline.reflink)("inside",inline._inside)();inline.normal=merge({},inline);inline.pedantic=merge({},inline.normal,{strong:/^__(?=S)([sS]*?S)__(?!_)|^**(?=S)([sS]*?S)**(?!*)/,em:/^_(?=S)([sS]*?S)_(?!_)|^*(?=S)([sS]*?S)*(?!*)/});inline.gfm=merge({},inline.normal,{escape:replace(inline.escape)("])","~|])")(),url:/^(https?://[^s<]+[^<.,:;"')]s])/,del:/^~~(?=S)([sS]*?S)~~/,text:replace(inline.text)("]|","~]|")("|","|https?://|")()});inline.breaks=merge({},inline.gfm,{br:replace(inline.br)("{2,}","*")(),text:replace(inline.gfm.text)("{2,}","*")()});function InlineLexer(links,options){this.options=options||marked.defaults;this.links=links;this.rules=inline.normal;this.renderer=this.options.renderer||new Renderer;this.renderer.options=this.options;if(!this.links){throw new Error("Tokens array requires a `links` property.")}if(this.options.gfm){if(this.options.breaks){this.rules=inline.breaks}else{this.rules=inline.gfm}}else if(this.options.pedantic){this.rules=inline.pedantic}}InlineLexer.rules=inline;InlineLexer.output=function(src,links,options){var inline=new InlineLexer(links,options);return inline.output(src)};InlineLexer.prototype.output=function(src){var out="",link,text,href,cap;while(src){if(cap=this.rules.escape.exec(src)){src=src.substring(cap[0].length);out+=cap[1];continue}if(cap=this.rules.autolink.exec(src)){src=src.substring(cap[0].length);if(cap[2]==="@"){text=cap[1].charAt(6)===":"?this.mangle(cap[1].substring(7)):this.mangle(cap[1]);href=this.mangle("mailto:")+text}else{text=escape(cap[1]);href=text}out+=this.renderer.link(href,null,text);continue}if(!this.inLink&&(cap=this.rules.url.exec(src))){src=src.substring(cap[0].length);text=escape(cap[1]);href=text;out+=this.renderer.link(href,null,text);continue}if(cap=this.rules.tag.exec(src)){if(!this.inLink&&/^<a /i.test(cap[0])){this.inLink=true}else if(this.inLink&&/^</a>/i.test(cap[0])){this.inLink=false}src=src.substring(cap[0].length);out+=this.options.sanitize?escape(cap[0]):cap[0];continue}if(cap=this.rules.link.exec(src)){src=src.substring(cap[0].length);this.inLink=true;out+=this.outputLink(cap,{href:cap[2],title:cap[3]});this.inLink=false;continue}if((cap=this.rules.reflink.exec(src))||(cap=this.rules.nolink.exec(src))){src=src.substring(cap[0].length);link=(cap[2]||cap[1]).replace(/s+/g," ");link=this.links[link.toLowerCase()];if(!link||!link.href){out+=cap[0].charAt(0);src=cap[0].substring(1)+src;continue}this.inLink=true;out+=this.outputLink(cap,link);this.inLink=false;continue}if(cap=this.rules.strong.exec(src)){src=src.substring(cap[0].length);out+=this.renderer.strong(this.output(cap[2]||cap[1]));continue}if(cap=this.rules.em.exec(src)){src=src.substring(cap[0].length);out+=this.renderer.em(this.output(cap[2]||cap[1]));continue}if(cap=this.rules.code.exec(src)){src=src.substring(cap[0].length);out+=this.renderer.codespan(escape(cap[2],true));continue}if(cap=this.rules.br.exec(src)){src=src.substring(cap[0].length);out+=this.renderer.br();continue}if(cap=this.rules.del.exec(src)){src=src.substring(cap[0].length);out+=this.renderer.del(this.output(cap[1]));continue}if(cap=this.rules.text.exec(src)){src=src.substring(cap[0].length);out+=escape(this.smartypants(cap[0]));continue}if(src){throw new Error("Infinite loop on byte: "+src.charCodeAt(0))}}return out};InlineLexer.prototype.outputLink=function(cap,link){var href=escape(link.href),title=link.title?escape(link.title):null;return cap[0].charAt(0)!=="!"?this.renderer.link(href,title,this.output(cap[1])):this.renderer.image(href,title,escape(cap[1]))};InlineLexer.prototype.smartypants=function(text){if(!this.options.smartypants)return text;return text.replace(/--/g,"—").replace(/(^|[-u2014/([{"s])'/g,"$1‘").replace(/'/g,"’").replace(/(^|[-u2014/([{u2018s])"/g,"$1“").replace(/"/g,"”").replace(/.{3}/g,"…")};InlineLexer.prototype.mangle=function(text){var out="",l=text.length,i=0,ch;for(;i<l;i++){ch=text.charCodeAt(i);if(Math.random()>.5){ch="x"+ch.toString(16)}out+="&#"+ch+";"}return out};function Renderer(options){this.options=options||{}}Renderer.prototype.code=function(code,lang,escaped){if(this.options.highlight){var out=this.options.highlight(code,lang);if(out!=null&&out!==code){escaped=true;code=out}}if(!lang){return"<pre><code>"+(escaped?code:escape(code,true))+"n</code></pre>"}return'<pre><code class="'+this.options.langPrefix+escape(lang,true)+'">'+(escaped?code:escape(code,true))+"n</code></pre>n"};Renderer.prototype.blockquote=function(quote){return"<blockquote>n"+quote+"</blockquote>n"};Renderer.prototype.html=function(html){return html};Renderer.prototype.heading=function(text,level,raw){return"<h"+level+' id="'+this.options.headerPrefix+raw.toLowerCase().replace(/[^w]+/g,"-")+'">'+text+"</h"+level+">n"};Renderer.prototype.hr=function(){return this.options.xhtml?"<hr/>n":"<hr>n"};Renderer.prototype.list=function(body,ordered){var type=ordered?"ol":"ul";return"<"+type+">n"+body+"</"+type+">n"};Renderer.prototype.listitem=function(text){return"<li>"+text+"</li>n"};Renderer.prototype.paragraph=function(text){return"<p>"+text+"</p>n"};Renderer.prototype.table=function(header,body){return"<table>n"+"<thead>n"+header+"</thead>n"+"<tbody>n"+body+"</tbody>n"+"</table>n"};Renderer.prototype.tablerow=function(content){return"<tr>n"+content+"</tr>n"};Renderer.prototype.tablecell=function(content,flags){var type=flags.header?"th":"td";var tag=flags.align?"<"+type+' style="text-align:'+flags.align+'">':"<"+type+">";return tag+content+"</"+type+">n"};Renderer.prototype.strong=function(text){return"<strong>"+text+"</strong>"};Renderer.prototype.em=function(text){return"<em>"+text+"</em>"};Renderer.prototype.codespan=function(text){return"<code>"+text+"</code>"};Renderer.prototype.br=function(){return this.options.xhtml?"<br/>":"<br>"};Renderer.prototype.del=function(text){return"<del>"+text+"</del>"};Renderer.prototype.link=function(href,title,text){if(this.options.sanitize){try{var prot=decodeURIComponent(unescape(href)).replace(/[^w:]/g,"").toLowerCase()}catch(e){return""}if(prot.indexOf("javascript:")===0){return""}}var out='<a href="'+href+'"';if(title){out+=' title="'+title+'"'}out+=">"+text+"</a>";return out};Renderer.prototype.image=function(href,title,text){var out='<img src="'+href+'" alt="'+text+'"';if(title){out+=' title="'+title+'"'}out+=this.options.xhtml?"/>":">";return out};function Parser(options){this.tokens=[];this.token=null;this.options=options||marked.defaults;this.options.renderer=this.options.renderer||new Renderer;this.renderer=this.options.renderer;this.renderer.options=this.options}Parser.parse=function(src,options,renderer){var parser=new Parser(options,renderer);return parser.parse(src)};Parser.prototype.parse=function(src){this.inline=new InlineLexer(src.links,this.options,this.renderer);this.tokens=src.reverse();var out="";while(this.next()){out+=this.tok()}return out};Parser.prototype.next=function(){return this.token=this.tokens.pop()};Parser.prototype.peek=function(){return this.tokens[this.tokens.length-1]||0};Parser.prototype.parseText=function(){var body=this.token.text;while(this.peek().type==="text"){body+="n"+this.next().text}return this.inline.output(body)};Parser.prototype.tok=function(){switch(this.token.type){case"space":{return""}case"hr":{return this.renderer.hr()}case"heading":{return this.renderer.heading(this.inline.output(this.token.text),this.token.depth,this.token.text)}case"code":{return this.renderer.code(this.token.text,this.token.lang,this.token.escaped)}case"table":{var header="",body="",i,row,cell,flags,j;cell="";for(i=0;i<this.token.header.length;i++){flags={header:true,align:this.token.align[i]};cell+=this.renderer.tablecell(this.inline.output(this.token.header[i]),{header:true,align:this.token.align[i]})}header+=this.renderer.tablerow(cell);for(i=0;i<this.token.cells.length;i++){row=this.token.cells[i];cell="";for(j=0;j<row.length;j++){cell+=this.renderer.tablecell(this.inline.output(row[j]),{header:false,align:this.token.align[j]})}body+=this.renderer.tablerow(cell)}return this.renderer.table(header,body)}case"blockquote_start":{var body="";while(this.next().type!=="blockquote_end"){body+=this.tok()}return this.renderer.blockquote(body)}case"list_start":{var body="",ordered=this.token.ordered;while(this.next().type!=="list_end"){body+=this.tok()}return this.renderer.list(body,ordered)}case"list_item_start":{var body="";while(this.next().type!=="list_item_end"){body+=this.token.type==="text"?this.parseText():this.tok()}return this.renderer.listitem(body)}case"loose_item_start":{var body="";while(this.next().type!=="list_item_end"){body+=this.tok()}return this.renderer.listitem(body)}case"html":{var html=!this.token.pre&&!this.options.pedantic?this.inline.output(this.token.text):this.token.text;return this.renderer.html(html)}case"paragraph":{return this.renderer.paragraph(this.inline.output(this.token.text))}case"text":{return this.renderer.paragraph(this.parseText())}}};function escape(html,encode){return html.replace(!encode?/&(?!#?w+;)/g:/&/g,"&amp;").replace(/</g,"&lt;").replace(/>/g,"&gt;").replace(/"/g,"&quot;").replace(/'/g,"&#39;")}function unescape(html){return html.replace(/&([#w]+);/g,function(_,n){n=n.toLowerCase();if(n==="colon")return":";if(n.charAt(0)==="#"){return n.charAt(1)==="x"?String.fromCharCode(parseInt(n.substring(2),16)):String.fromCharCode(+n.substring(1))}return""})}function replace(regex,opt){regex=regex.source;opt=opt||"";return function self(name,val){if(!name)return new 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highlight(token.text,token.lang,function(err,code){if(code==null||code===token.text){return--pending||done()}token.text=code;token.escaped=true;--pending||done()})})(tokens[i])}return}try{if(opt)opt=merge({},marked.defaults,opt);return Parser.parse(Lexer.lex(src,opt),opt)}catch(e){e.message+="nPlease report this to https://github.com/chjj/marked.";if((opt||marked.defaults).silent){return"<p>An error occured:</p><pre>"+escape(e.message+"",true)+"</pre>"}throw e}}marked.options=marked.setOptions=function(opt){merge(marked.defaults,opt);return marked};marked.defaults={gfm:true,tables:true,breaks:false,pedantic:false,sanitize:false,smartLists:false,silent:false,highlight:null,langPrefix:"lang-",smartypants:false,headerPrefix:"",renderer:new Renderer,xhtml:false};marked.Parser=Parser;marked.parser=Parser.parse;marked.Renderer=Renderer;marked.Lexer=Lexer;marked.lexer=Lexer.lex;marked.InlineLexer=InlineLexer;marked.inlineLexer=InlineLexer.output;marked.parse=marked;if(typeof exports==="object"){module.exports=marked}else if(typeof define==="function"&&define.amd){define(function(){return marked})}else{this.marked=marked}}).call(function(){return this||(typeof window!=="undefined"?window:global)}()); </ins>  No newline at end of file

Related discussion:
text: Since copy+pasting our code makes it too easy for people to XSS themselves, lets just add a comment in there about it.
PR at - let me know if that's what you had in mind!
My intuition is that it makes more sense to fix the example (call a sanitization library) or to change the example completely (demonstrate something else that is safer). It looks really bad to have a security warning on the homepage of the react site. Makes it seem like our framework encourages unsafe operations, rather than a safe-by-default way of doing things.
Should switch the demo to use a different library like markdown-js that escapes everything and doesn't support HTML:
markdown-js looks good. First attempt: ,output Code licensed if someone wants to turn this into a coherent example; I've signed the CLA.
That's a good suggestion too :) - what are your thoughts? I'm happy to change the example to use like people have suggested above. nice usage example :+1:
Uh yea, that sounds fine to me. This behavior is definitely non-standard markdown but it's an example so not a big deal. We should probably do the same for the tutorial while we're here. And it's on cdnjs so that's all pretty easy:
Just going to use marked instead, which I'm already familiar with and has an option to sanitize input.