Conditional Content

In some cases you may want to create content that only displays for a given output format (or only displays when not rendering to a format). You can accomplish this by creating divs, spans and code blocks with the .content-visible and .content-hidden classes.

.content-visible

To make content visible only for a given format, you can create a div (:::) with the .content-visible class. For example, here we mark content as only visible in HTML:

::: {.content-visible when-format="html"}

Will only appear in HTML.

:::

You can also set conditions on non-executable code blocks:

```{.python .content-visible when-format="html"}
# code shown only in HTML
2+2
```

To apply a condition only to a part of a paragraph, use a span ([]{}):

Some text
[in HTML.]{.content-visible when-format="html"}
[in PDF.]{.content-visible when-format="pdf"}

You can also mark content as visible for all formats except a specified format. For example:

::: {.content-visible unless-format="pdf"}

Will not appear in PDF.

:::

Then when-format and unless-format attributes match the current Pandoc output format with some additional intelligence to alias related formats (e.g. html, html4, and html5). Details are provided below in Format Matching

when-format and unless-format can also be combined to create more complex conditions:

::: {.content-visible when-format="html" unless-format="revealjs"}

Will only appear in HTML and not in Reveal.js, but actually it appears.

:::

::: {.content-visible when-format="revealjs"}

Will only appear in Reveal.js and not in HTML or other formats.

:::

.content-hidden

To prevent content from being displayed when rendering to a given format, use the .content-hidden class. For example, here we mark content as hidden in HTML:

::: {.content-hidden when-format="html"}

Will not appear in HTML.

:::

You can also mark content as hidden for all formats except a specified format. For example:

::: {.content-hidden unless-format="pdf"}

Will only appear in PDF.

:::

Format Matching

Then when-format and unless-format clauses do some aliasing of related formats to make it more straightforward to target content. The following aliases are implemented:

Alias	Formats
latex	latex, pdf
pdf	latex, pdf
epub	epub*
html	html*, epub*, revealjs
html:js	html*, revealjs
markdown	markdown*, commonmark*, gfm, markua

Note that the html:js alias indicates that the target format is capable of executing JavaScript (this maps to all HTML formats save for ePub).