Giulia Chiola

Posted on Jan 20, 2021 • Updated on Jun 12, 2021 • Originally published at giuliachiola.dev

Add HTML classes to 11ty markdown content

#11ty #eleventy

11ty comes with some useful plugins for markdown manipulation, one of these is markdown-it-attrs.

This plugin should be used combined with its big brother, the markdown parser markdown-it, which is already added in 11ty basic installation.

markdown-it-attrs uses markdown-it and add the possibility to add attributes to HTML nodes generated from markdown.

To use it, add this plugin to the .eleventy configuration file:

require markdown-it

const markdownIt = require('markdown-it')

require markdown-it-attrs

const markdownItAttrs = require('markdown-it-attrs')

define basic markdown-it configuration options

const markdownItOptions = {
  html: true,
  breaks: true,
  linkify: true
}

set markdown-it-attrs as markdown-it usage options

const markdownLib = markdownIt(markdownItOptions).use(markdownItAttrs)

set as eleventy configuration the new markdown configuration

eleventyConfig.setLibrary('md', markdownLib)

To sum up:

// .eleventy.js

const markdownIt = require('markdown-it')
const markdownItAttrs = require('markdown-it-attrs')

const markdownItOptions = {
  html: true,
  breaks: true,
  linkify: true
}

const markdownLib = markdownIt(markdownItOptions).use(markdownItAttrs)
eleventyConfig.setLibrary('md', markdownLib)

Example of usage

# This is a title {.c-article-section__title}
This is a paragraph with data-state {data-state=important}

Another text with attributes {.c-article-section__disclaimer #articleId attr=value attr2="spaced value"}

![Alt text](image.jpg){.u-shadow}

[Link in a new tab](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a){target="_blank" rel="noopener"}

will output

<h1 class="c-article-section__title">This is a title</h1>
<p data-state=important>This is a paragraph with data-state</p>
<p class="c-article-section__disclaimer" id="articleId" attr=value attr2="spaced value">Another text with attributes</p>

<img class="u-shadow" src="image.jpg" alt="Alt text">
<a href="https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a" target="_blank" rel="noopener">Link in a new tab</a>

🧨 !important

Note the last line where I added the target="_blank" attribute to the link to open it in a new browser tab. It's ok open a link in a new tab, but for security reasons it has to have also the rel="noopener" attribute.

Side note: unfortunately, I did not find a way to add attributes to markdown tables and blockquote 😢

📚 More info

11ty Markdown Attributes

When to use target="_blank” by Chris Coyer

rel="noopener" - MDN

Top comments (4)

Joren Broekema • Apr 26 '21

I think you forgot .u-shadow class in the image tag in the output right?

Giulia Chiola • Jun 12 '21

Thank you Joren! 🙃 I just noticed that I also forgot to add the ALT text in the output 😇 I have just fixed both. Have a nice day!

Joren Broekema • Jun 12 '21

Thank you :) cool tips btw, we are using 11ty and actually were wondering if there was an easy way to change how markup is spit out from the markdown, mostly adding classes, so we can style our content better. This helps!