Markdown to HTML Conversion Expert skill for converting Markdown documents to HTML using the marked.js library, or writing data conversion scripts; in this case scripts similar to markedJS/marked repository. For custom scripts knowledge is not confined to marked.js , but data conversion methods are utilized from tools like pandoc and gomarkdown/markdown for data conversion; jekyll/jekyll and gohugoio/hugo for templating systems. The conversion script or tool should handle single files, batch conversions, and advanced configurations. When to Use This Skill User asks to "convert markdown to html" or "transform md files" User wants to "render markdown" as HTML output User needs to generate HTML documentation from .md files User is building static sites from Markdown content User is building template system that converts markdown to html User is working on a tool, widget, or custom template for an existing templating system User wants to preview Markdown as rendered HTML Converting Markdown to HTML Essential Basic Conversions For more see basic-markdown-to-html.md

# Level 1
## Level 2
One sentence with a [link](https://example.com), and a HTML snippet like `<p>paragraph tag</p>`.
- `ul` list item 1
- `ul` list item 2
1. `ol` list item 1
2. `ol` list item 1
| Table Item | Description |
| One | One is the spelling of the number `1`. |
| Two | Two is the spelling of the number `2`. |
```js
var one = 1;
var two = 2;
function simpleMath(x, y) {
return x + y;
}
console.log(simpleMath(one, two));

```html
<h1>Level 1</h1>
<h2>Level 2</h2>
<p>One sentence with a <a href="https://example.com">link</a>, and a HTML snippet like <code>&lt;p&gt;paragraph tag&lt;/p&gt;</code>.</p>
<ul>
<li>`ul` list item 1</li>
<li>`ul` list item 2</li>
</ul>
<ol>
<li>`ol` list item 1</li>
<li>`ol` list item 2</li>
</ol>
<table>
<thead>
<tr>
<th>Table Item</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr>
<td>One</td>
<td>One is the spelling of the number `1`.</td>
</tr>
<tr>
<td>Two</td>
<td>Two is the spelling of the number `2`.</td>
</tr>
</tbody>
</table>
<pre>
<code>var one = 1;
var two = 2;
function simpleMath(x, y) {
return x + y;
}
console.log(simpleMath(one, two));</code>
</pre>

Code Block Conversions For more see code-blocks-to-html.md

your code here

<pre><code class="language-md">
your code here
</code></pre>

console.log("Hello world");

<pre><code class="language-js">
console.log("Hello world");
</code></pre>

visible backticks

<pre><code>

visible backticks

</code></pre>

Collapsed Section Conversions For more see collapsed-sections-to-html.md

<details>
<summary>More info</summary>
### Header inside
- Lists
- **Formatting**
- Code blocks
```js
console.log("Hello");

```html
<details>
<summary>More info</summary>
<h3>Header inside</h3>
<ul>
<li>Lists</li>
<li><strong>Formatting</strong></li>
<li>Code blocks</li>
</ul>
<pre>
<code class="language-js">console.log("Hello");</code>
</pre>
</details>

Mathematical Expression Conversions For more see writing-mathematical-expressions-to-html.md

This sentence uses `$` delimiters to show math inline: $\sqrt{3x-1}+(1+x)^2$

<p>This sentence uses <code>$</code> delimiters to show math inline:
<math-renderer><math xmlns="http://www.w3.org/1998/Math/MathML">
<msqrt><mn>3</mn><mi>x</mi><mo>−</mo><mn>1</mn></msqrt>
<mo>+</mo><mo>(</mo><mn>1</mn><mo>+</mo><mi>x</mi>
<msup><mo>)</mo><mn>2</mn></msup>
</math>
</math-renderer>
</p>

**The Cauchy-Schwarz Inequality**\
$$\left( \sum_{k=1}^n a_k b_k \right)^2 \leq \left( \sum_{k=1}^n a_k^2 \right) \left( \sum_{k=1}^n b_k^2 \right)$$

<p><strong>The Cauchy-Schwarz Inequality</strong><br>
<math-renderer>
<math xmlns="http://www.w3.org/1998/Math/MathML">
<msup>
<mrow><mo>(</mo>
<munderover><mo data-mjx-texclass="OP">∑</mo>
<mrow><mi>k</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi>
</munderover>
<msub><mi>a</mi><mi>k</mi></msub>
<msub><mi>b</mi><mi>k</mi></msub>
<mo>)</mo>
</mrow>
<mn>2</mn>
</msup>
<mo>≤</mo>
<mrow><mo>(</mo>
<munderover><mo>∑</mo>
<mrow><mi>k</mi><mo>=</mo><mn>1</mn></mrow>
<mi>n</mi>
</munderover>
<msubsup><mi>a</mi><mi>k</mi><mn>2</mn></msubsup>
<mo>)</mo>
</mrow>
<mrow><mo>(</mo>
<munderover><mo>∑</mo>
<mrow><mi>k</mi><mo>=</mo><mn>1</mn></mrow>
<mi>n</mi>
</munderover>
<msubsup><mi>b</mi><mi>k</mi><mn>2</mn></msubsup>
<mo>)</mo>
</mrow>
</math>
</math-renderer></p>

Table Conversions For more see tables-to-html.md

| First Header  | Second Header |
| ------------- | ------------- |
| Content Cell  | Content Cell  |
| Content Cell  | Content Cell  |

<table>
<thead><tr><th>First Header</th><th>Second Header</th></tr></thead>
<tbody>
<tr><td>Content Cell</td><td>Content Cell</td></tr>
<tr><td>Content Cell</td><td>Content Cell</td></tr>
</tbody>
</table>

| Left-aligned | Center-aligned | Right-aligned |
| :---         |     :---:      |          ---: |
| git status   | git status     | git status    |
| git diff     | git diff       | git diff      |

<table>
<thead>
<tr>
<th align="left">Left-aligned</th>
<th align="center">Center-aligned</th>
<th align="right">Right-aligned</th>
</tr>
</thead>
<tbody>
<tr>
<td align="left">git status</td>
<td align="center">git status</td>
<td align="right">git status</td>
</tr>
<tr>
<td align="left">git diff</td>
<td align="center">git diff</td>
<td align="right">git diff</td>
</tr>
</tbody>
</table>

Working with markedJS/marked Prerequisites Node.js installed (for CLI or programmatic usage) Install marked globally for CLI: npm install -g marked Or install locally: npm install marked Quick Conversion Methods See marked.md Quick Conversion Methods Step-by-Step Workflows See marked.md Step-by-Step Workflows CLI Configuration Using Config Files Create ~/.marked.json for persistent options: { "gfm" : true , "breaks" : true } Or use a custom config: marked -i input.md -o output.html -c config.json CLI Options Reference Option Description -i, --input Input Markdown file -o, --output Output HTML file -s, --string Parse string instead of file -c, --config Use custom config file --gfm Enable GitHub Flavored Markdown --breaks Convert newlines to
--help Show all options Security Warning ⚠️ Marked does NOT sanitize output HTML. For untrusted input, use a sanitizer: import { marked } from 'marked' ; import DOMPurify from 'dompurify' ; const unsafeHtml = marked . parse ( untrustedMarkdown ) ; const safeHtml = DOMPurify . sanitize ( unsafeHtml ) ; Recommended sanitizers: DOMPurify (recommended) sanitize-html js-xss Supported Markdown Flavors Flavor Support Original Markdown 100% CommonMark 0.31 98% GitHub Flavored Markdown 97% Troubleshooting Issue Solution Special characters at file start Strip zero-width chars: content.replace(/^[\u200B\u200C\u200D\uFEFF]/,"") Code blocks not highlighting Add a syntax highlighter like highlight.js Tables not rendering Ensure gfm: true option is set Line breaks ignored Set breaks: true in options XSS vulnerability concerns Use DOMPurify to sanitize output Working with pandoc Prerequisites Pandoc installed (download from https://pandoc.org/installing.html ) For PDF output: LaTeX installation (MacTeX on macOS, MiKTeX on Windows, texlive on Linux) Terminal/command prompt access Quick Conversion Methods Method 1: CLI Basic Conversion

Convert markdown to HTML

pandoc input.md -o output.html

Convert with standalone document (includes header/footer)

pandoc input.md -s -o output.html

Explicit format specification

pandoc input.md -f markdown -t html -s -o output.html Method 2: Filter Mode (Interactive)

Start pandoc as a filter

pandoc

Type markdown, then Ctrl-D (Linux/macOS) or Ctrl-Z+Enter (Windows)

Hello pandoc !

Output:
Hello pandoc!

Method 3: Format Conversion

HTML to Markdown

pandoc -f html -t markdown input.html -o output.md

Markdown to LaTeX

pandoc input.md -s -o output.tex

Markdown to PDF (requires LaTeX)

pandoc input.md -s -o output.pdf

Markdown to Word

pandoc input.md -s -o output.docx CLI Configuration Option Description -f, --from Input format (markdown, html, latex, etc.) -t, --to Output format (html, latex, pdf, docx, etc.) -s, --standalone Produce standalone document with header/footer -o, --output Output file (inferred from extension) --mathml Convert TeX math to MathML --metadata title="Title" Set document metadata --toc Include table of contents --template Use custom template --help Show all options Security Warning ⚠️ Pandoc processes input faithfully. When converting untrusted markdown: Use --sandbox mode to disable external file access Validate input before processing Sanitize HTML output if displayed in browsers

Run in sandbox mode for untrusted input

pandoc --sandbox input.md -o output.html Supported Markdown Flavors Flavor Support Pandoc Markdown 100% (native) CommonMark Full (use -f commonmark ) GitHub Flavored Markdown Full (use -f gfm ) MultiMarkdown Partial Troubleshooting Issue Solution PDF generation fails Install LaTeX (MacTeX, MiKTeX, or texlive) Encoding issues on Windows Run chcp 65001 before using pandoc Missing standalone headers Add -s flag for complete documents Math not rendering Use --mathml or --mathjax option Tables not rendering Ensure proper table syntax with pipes and dashes Working with gomarkdown/markdown Prerequisites Go 1.18 or higher installed Install the library: go get github.com/gomarkdown/markdown For CLI tool: go install github.com/gomarkdown/mdtohtml@latest Quick Conversion Methods Method 1: Simple Conversion (Go) package main import ( "fmt" "github.com/gomarkdown/markdown" ) func main ( ) { md := [ ] byte ( "# Hello World\n\nThis is bold text." ) html := markdown . ToHTML ( md , nil , nil ) fmt . Println ( string ( html ) ) } Method 2: CLI Tool

Install mdtohtml

go install github.com/gomarkdown/mdtohtml@latest

Convert file

mdtohtml input.md output.html

Convert file (output to stdout)

mdtohtml input.md Method 3: Custom Parser and Renderer package main import ( "github.com/gomarkdown/markdown" "github.com/gomarkdown/markdown/html" "github.com/gomarkdown/markdown/parser" ) func mdToHTML ( md [ ] byte ) [ ] byte { // Create parser with extensions extensions := parser . CommonExtensions | parser . AutoHeadingIDs | parser . NoEmptyLineBeforeBlock p := parser . NewWithExtensions ( extensions ) doc := p . Parse ( md ) // Create HTML renderer with extensions htmlFlags := html . CommonFlags | html . HrefTargetBlank opts := html . RendererOptions { Flags : htmlFlags } renderer := html . NewRenderer ( opts ) return markdown . Render ( doc , renderer ) } CLI Configuration The mdtohtml CLI tool has minimal options: mdtohtml input-file [ output-file ] For advanced configuration, use the Go library programmatically with parser and renderer options: Parser Extension Description parser.CommonExtensions Tables, fenced code, autolinks, strikethrough, etc. parser.AutoHeadingIDs Generate IDs for headings parser.NoEmptyLineBeforeBlock No blank line needed before blocks parser.MathJax MathJax support for LaTeX math HTML Flag Description html.CommonFlags Common HTML output flags html.HrefTargetBlank Add target="_blank" to links html.CompletePage Generate complete HTML page html.UseXHTML Generate XHTML output Security Warning ⚠️ gomarkdown does NOT sanitize output HTML. For untrusted input, use Bluemonday: import ( "github.com/microcosm-cc/bluemonday" "github.com/gomarkdown/markdown" ) maybeUnsafeHTML := markdown . ToHTML ( md , nil , nil ) html := bluemonday . UGCPolicy ( ) . SanitizeBytes ( maybeUnsafeHTML ) Recommended sanitizer: Bluemonday Supported Markdown Flavors Flavor Support Original Markdown 100% CommonMark High (with extensions) GitHub Flavored Markdown High (tables, fenced code, strikethrough) MathJax/LaTeX Math Supported via extension Mmark Supported Troubleshooting Issue Solution Windows/Mac newlines not parsed Use parser.NormalizeNewlines(input) Tables not rendering Enable parser.Tables extension Code blocks without highlighting Integrate with syntax highlighter like Chroma Math not rendering Enable parser.MathJax extension XSS vulnerabilities Use Bluemonday to sanitize output Working with jekyll Prerequisites Ruby version 2.7.0 or higher RubyGems GCC and Make (for native extensions) Install Jekyll and Bundler: gem install jekyll bundler Quick Conversion Methods Method 1: Create New Site

Create a new Jekyll site

jekyll new myblog

Change to site directory

cd myblog

Build and serve locally

bundle exec jekyll serve

Access at http://localhost:4000

Method 2: Build Static Site

Build site to _site directory

bundle exec jekyll build

Build with production environment

JEKYLL_ENV

production bundle exec jekyll build Method 3: Live Reload Development

Serve with live reload

bundle exec jekyll serve --livereload

Serve with drafts

bundle exec jekyll serve --drafts CLI Configuration Command Description jekyll new Create new Jekyll site jekyll build Build site to _site directory jekyll serve Build and serve locally jekyll clean Remove generated files jekyll doctor Check for configuration issues Serve Options Description --livereload Reload browser on changes --drafts Include draft posts --port Set server port (default: 4000) --host Set server host (default: localhost) --baseurl Set base URL Security Warning ⚠️ Jekyll security considerations: Avoid using safe: false in production Use exclude in _config.yml to prevent sensitive files from being published Sanitize user-generated content if accepting external input Keep Jekyll and plugins updated

_config.yml security settings

exclude : - Gemfile - Gemfile.lock - node_modules - vendor Supported Markdown Flavors Flavor Support Kramdown (default) 100% CommonMark Via plugin (jekyll-commonmark) GitHub Flavored Markdown Via plugin (jekyll-commonmark-ghpages) RedCarpet Via plugin (deprecated) Configure markdown processor in _config.yml : markdown : kramdown kramdown : input : GFM syntax_highlighter : rouge Troubleshooting Issue Solution Ruby 3.0+ fails to serve Run bundle add webrick Gem dependency errors Run bundle install Slow builds Use --incremental flag Liquid syntax errors Check for unescaped { in content Plugin not loading Add to _config.yml plugins list Working with hugo Prerequisites Hugo installed (download from https://gohugo.io/installation/ ) Git (recommended for themes and modules) Go (optional, for Hugo Modules) Quick Conversion Methods Method 1: Create New Site

Create a new Hugo site

hugo new site mysite

Change to site directory

cd mysite

Add a theme

git init git submodule add https://github.com/theNewDynamic/gohugo-theme-ananke themes/ananke echo "theme = 'ananke'"

hugo.toml

Create content

hugo new content posts/my-first-post.md

Start development server

hugo server -D Method 2: Build Static Site

Build site to public directory

hugo

Build with minification

hugo --minify

Build for specific environment

hugo --environment production Method 3: Development Server

Start server with drafts

hugo server -D

Start with live reload and bind to all interfaces

hugo server --bind 0.0 .0.0 --baseURL http://localhost:1313/

Start with specific port

hugo server --port 8080 CLI Configuration Command Description hugo new site Create new Hugo site hugo new content Create new content file hugo Build site to public directory hugo server Start development server hugo mod init Initialize Hugo Modules Build Options Description -D, --buildDrafts Include draft content -E, --buildExpired Include expired content -F, --buildFuture Include future-dated content --minify Minify output --gc Run garbage collection after build -d, --destination Output directory Server Options Description --bind Interface to bind to -p, --port Port number (default: 1313) --liveReloadPort Live reload port --disableLiveReload Disable live reload --navigateToChanged Navigate to changed content Security Warning ⚠️ Hugo security considerations: Configure security policy in hugo.toml for external commands Use --enableGitInfo carefully with public repositories Validate shortcode parameters for user-generated content

hugo.toml security settings

[ security ] enableInlineShortcodes = false [ security.exec ] allow = [ '^go$' , '^npx$' , '^postcss$' ] [ security.funcs ] getenv = [ '^HUGO_' , '^CI$' ] [ security.http ] methods = [ '(?i)GET|POST' ] urls = [ '.*' ] Supported Markdown Flavors Flavor Support Goldmark (default) 100% (CommonMark compliant) GitHub Flavored Markdown Full (tables, strikethrough, autolinks) CommonMark 100% Blackfriday (legacy) Deprecated, not recommended Configure markdown in hugo.toml : [ markup ] [ markup.goldmark ] [ markup.goldmark.extensions ] definitionList = true footnote = true linkify = true strikethrough = true table = true taskList = true [ markup.goldmark.renderer ] unsafe = false

Set true to allow raw HTML

Troubleshooting Issue Solution "Page not found" on paths Check baseURL in config Theme not loading Verify theme in themes/ or Hugo Modules Slow builds Use --templateMetrics to identify bottlenecks Raw HTML not rendering Set unsafe = true in goldmark config Images not loading Check static/ folder structure Module errors Run hugo mod tidy References Writing and Styling Markdown basic-markdown.md code-blocks.md collapsed-sections.md tables.md writing-mathematical-expressions.md Markdown Guide: https://www.markdownguide.org/basic-syntax/ Styling Markdown: https://github.com/sindresorhus/github-markdown-css markedJS/marked Official documentation: https://marked.js.org/ Advanced options: https://marked.js.org/using_advanced Extensibility: https://marked.js.org/using_pro GitHub repository: https://github.com/markedjs/marked pandoc Getting started: https://pandoc.org/getting-started.html Official documentation: https://pandoc.org/MANUAL.html Extensibility: https://pandoc.org/extras.html GitHub repository: https://github.com/jgm/pandoc gomarkdown/markdown Official documentation: https://pkg.go.dev/github.com/gomarkdown/markdown Advanced configuration: https://pkg.go.dev/github.com/gomarkdown/markdown@v0.0.0-20250810172220-2e2c11897d1a/html Markdown processing: https://blog.kowalczyk.info/article/cxn3/advanced-markdown-processing-in-go.html GitHub repository: https://github.com/gomarkdown/markdown jekyll Official documentation: https://jekyllrb.com/docs/ Configuration options: https://jekyllrb.com/docs/configuration/options/ Plugins: https://jekyllrb.com/docs/plugins/ Installation Generators Converters Commands Tags Filters Hooks GitHub repository: https://github.com/jekyll/jekyll hugo Official documentation: https://gohugo.io/documentation/ All Settings: https://gohugo.io/configuration/all/ Editor Plugins: https://gohugo.io/tools/editors/ GitHub repository: https://github.com/gohugoio/hugo

安装

Convert markdown to HTML

Convert with standalone document (includes header/footer)

Explicit format specification

Start pandoc as a filter

Type markdown, then Ctrl-D (Linux/macOS) or Ctrl-Z+Enter (Windows)

Output: Hello pandoc!

HTML to Markdown

Markdown to LaTeX

Markdown to PDF (requires LaTeX)

Markdown to Word

Run in sandbox mode for untrusted input

Install mdtohtml

Convert file

Convert file (output to stdout)

Create a new Jekyll site

Change to site directory

Build and serve locally

Access at http://localhost:4000

Build site to _site directory

Build with production environment

JEKYLL_ENV

Serve with live reload

Serve with drafts

_config.yml security settings

Create a new Hugo site

Change to site directory

Add a theme

Create content

Start development server

Build site to public directory

Build with minification

Build for specific environment

Start server with drafts

Start with live reload and bind to all interfaces

Start with specific port

hugo.toml security settings

Set true to allow raw HTML

Output:
Hello pandoc!