By Andrew Clark

Transform Markdown footnotes into superpowered1 sidenotes.

Try it out now by changing the size of your browser window. At full width, notes on this page are rendered as sidenotes. At medium width, they are placed directly after their reference in the text. At small widths, they are rendered as normal footnotes.

You can also use this page’s key bindings to experiment with the API. For example, press h and watch what happens. (Press s to reverse the change.)


  • Transform your footnotes into sidenotes.
  • Toggle between footnotes and sidenotes, for instance, in responsive designs.
  • Toggle between placing the sidenotes before2 or after their reference in the text.
  • Enable reference-less (numberless) sidenotes, using a custom regular expression.3
  • Works with any Markdown processor.
  • Nested footnotes (footnotes inside footnotes) work, too!


Grab jquery.sidenotes.min.js from the GitHub repo, upload it to a server, and add it to your document’s head:

<script src="jquery.sidenotes.min.js"></script>

With Bower

jQuery.sidenotes is available as a Bower package.

bower install jquery.sidenotes --save


Use of jQuery.sidenotes requires a working knowledge of JavaScript, jQuery, and CSS. I realize this can be frustrating for non-programmers, who may wish for a one-size-fits-all approach. Please submit an issue if you have any usability concerns or suggestions.

Apply the plugin to a jQuery object consisting of each post/document container on the page. The post container can be any ancestor element of the Markdown-generated content, but there must be only one post container per post.4

With no configuration (use sensible defaults):


Or, pass an options object:

  'removeRefMarkRegex':     /-sn$/,
  'initiallyHidden':        true


By default, footnotes are transformed into aside elements and placed into the document near their reference.

Please note that, by design, jQuery.sidenotes does not apply any CSS styling. It’s up to you to style the generated sidenotes using appropriate selectors.5


Built-in methods allow you to toggle between footnotes and sidenotes.

// Hide the sidenotes, show the footnotes

// Show the sidenotes, hide the footnotes

This is perfect for responsive designs, where you may only want to use sidenotes when the screen is large enough to accomodate them.

By default, sidenotes are placed before their reference in the text. This is due to the expectation that most designers will want to float them so that they are adjacent to their reference. However, if the sidenotes are not floated, it’s probably better to place them after their reference in the text, so that the note does not appear before the reference. You can update the sidenotePlacement property to toggle between the two states.

// Place the sidenotes after their references
$('.post').sidenotes('sidenotePlacement', 'after')

// Place the sidenotes before their references
$('.post').sidenotes('sidenotePlacement', 'before')

You can set the initial sidenotePlacement in the options object.


jQuery.sidenotes is designed to work with zero configuration while also being highly configurable. You can set the following options by passing them as a JSON object to the plugin constructor.


By default, the sidenotes are shown immediately after they are created during plugin initialization. By setting this to true, the sidenotes will remain hidden until explicitly shown with $.fn.asides('show').

Default: false


By default, the sidenotes are initially placed before their reference in the text, with the expectation that they will be floated. To place them after their reference, set this to 'after'.

Default: 'before'


Use to enable numberless, or reference-less, sidenotes. Footnote IDs that match this regular expression will be displayed without a number.6 The reference mark in the document will be hidden, and the notes that follow will be renumbered accordingly. When the sidenotes are hidden, the original references are restored.

The default regular expression will not match any footnote.

Default: /(?!)/


The element type of the sidenotes.

Default: 'aside'


Sidenotes7 that are placed next to each other8 in the document are automatically wrapped in a container element. This is the element type of the container.

Default: 'div'


The class that is added to each sidenote.

Default: 'sidenote'


The class that is added to each group.

Default: 'sidenote-group'


The class that is added to each sidenote’s reference mark.

Default: 'ref-mark'

Additional options for selectors

There is some variation in how Markdown processors generate the markup for footnotes. The default options have been chosen to work across all of them, but if they do not, trying passing a new footnoteContainerSelector or footnoteSelector as options. If you’re still having problems with your Markdown processor, please submit an issue.


jQuery selector string for the footnote container. This selector is run within the context of the post container.

Default: '.footnotes'


jQuery selector string for the footnotes. This selector is run within the context of the footnote container.

Default: '> ol > li'


On this page, you can use the following key bindings to test the API:

  • s – $.fn.sidenotes('show')
  • h – $.fn.sidenotes('hide')
  • b – $.fn.sidenotes('sidenotePlacement', 'before')
  • a – $.fn.sidenotes('sidenotePlacement', 'after')


Sets up the document. Apply to each post/document container. A post container must contain both the content of the post and its footnotes.

Optionally, you can pass an options object.


Shows the sidenotes and hides the footnotes.


Hides the sidenotes and shows the footnotes.


Returns true if the sidenotes are hidden.

$.fn.sidenotes(‘sidenotePlacement’, placement)

Changes the placement of the sidenotes to either before or after their references in the text. Accepted values are 'before' or 'after'.

If no arguments are passed, or if the placement argument is invalid, this returns the current sidenotePlacement.


Destroys the plugin instance. Removes the sidenotes and shows the footnotes.


  • jQuery
  • Markdown-generated content, or markup that mimics it.


If you use this plugin in one of your projects, please let me know9 and I’ll add it here.


Copyright 2013
Andrew Clark

Licensed under the MIT License

  1. Wanna see something cool? Resize this page and watch how this note adapts to different screen sizes.

  2. Useful for floated sidenotes.

  3. This sidenote doesn’t have a reference.

  4. If you’re experiencing unexpected behavior, this is likely your problem.

  5. You can use CSS media queries to target specific screen sizes.

  6. This page’s removeRefMarkRegex is /-sn$/, and the footnote ID corresponding to this note is fn:refless-sn. Therefore, the sidenote is rendered without a reference.

  7. This sidenote and the next one…

  8. … are part of a sidenote group.

  9. Or even better, submit a pull request.