[css] Can I define a class name on paragraph using Markdown?

Can I define a class name on paragraph using Markdown? If so, how?

Here is a working example for kramdown following @Yarin's answer.

A simple paragraph with a class attribute.
{:.yourClass}

Reference: https://kramdown.gettalong.org/syntax.html#inline-attribute-lists

If your flavour of markdown is kramdown, then you can set css class like this:

{:.nameofclass}
paragraph is here

Then in you css file, you set the css like this:

.nameofclass{
   color: #000;
  }

In slim markdown use this:

markdown:
  {:.cool-heading}
  #Some Title

Translates to:

<h1 class="cool-heading">Some Title</h1>

If your environment is JavaScript, use markdown-it along with the plugin markdown-it-attrs:

const md = require('markdown-it')();
const attrs = require('markdown-it-attrs');
md.use(attrs);

const src = 'paragraph {.className #id and=attributes}';

// render
let res = md.render(src);
console.log(res);

Output

<p class="className" id="id" and="attributes">paragraph</p>

jsfiddle

Note: Be aware of the security aspect when allowing attributes in your markdown!

Disclaimer, I'm the author of markdown-it-attrs.

It should also be mentioned that <span> tags allow inside them -- block-level items negate MD natively inside them unless you configure them not to do so, but in-line styles natively allow MD within them. As such, I often do something akin to...

This is a superfluous paragraph thing.

<span class="class-red">And thus I delve into my topic, Lorem ipsum lollipop bubblegum.</span>

And thus with that I conclude.

I am not 100% sure if this is universal but seems to be the case in all MD editors I've used.

If you just need a selector for Javascript purposes (like I did), you might just want to use a href attribute instead of a class or id:

Just do this:

<a href="#foo">Link</a>

Markdown will not ignore or remove the href attribute like it does with classes and ids.

So in your Javascript or jQuery you can then do:

$('a[href$="foo"]').click(function(event) {

    ... do your thing ...

    event.preventDefault();
});

At least this works in my version of Markdown...

Raw HTML is actually perfectly valid in markdown. For instance:

Normal *markdown* paragraph.

<p class="myclass">This paragraph has a class "myclass"</p>

Just make sure the HTML is not inside a code block.

Markdown should have this capability, but it doesn't. Instead, you're stuck with language-specific Markdown supersets:

PHP: Markdown Extra
Ruby: Kramdown, Maruku

But if you need to abide by true Markdown syntax, you're stuck with inserting raw HTML, which is less ideal.

As mentioned above markdown itself leaves you hanging on this. However, depending on the implementation there are some workarounds:

At least one version of MD considers <div> to be a block level tag but <DIV> is just text. All broswers however are case insensitive. This allows you to keep the syntax simplicity of MD, at the cost of adding div container tags.

So the following is a workaround:

<DIV class=foo>

  Paragraphs here inherit class foo from above.

</div>

The downside of this is that the output code has <p> tags wrapping the <div> lines (both of them, the first because it's not and the second because it doesn't match. No browser fusses about this that I've found, but the code won't validate. MD tends to put in spare <p> tags anyway.

Several versions of markdown implement the convention <tag markdown="1"> in which case MD will do the normal processing inside the tag. The above example becomes:

<div markdown="1" class=foo>

  Paragraphs here inherit class foo from above.

</div>

The current version of Fletcher's MultiMarkdown allows attributes to follow the link if using referenced links.