![Showdown][sd-logo]

---

Showdown is a Javascript Markdown to HTML converter, based on the original works by John Gruber. Showdown can be used client side (in the browser) or server side (with NodeJs).

Live DEMO

Check a live Demo here http://demo.showdownjs.com/

Funding

As you know, ShowdownJS is a free library and it will remain free forever. However, maintaining and improving the library costs time and money.

If you like our work and find our library useful, please donate through paypal!! Your contribution will be greatly appreciated and help us continue to develop this awesome library.

License

ShowdownJS v 2.0 is release under the MIT version. Previous versions are release under BSD.

Who uses Showdown (or a fork)

• GoogleCloudPlatform
• Meteor
• Stackexchange - forked as PageDown
• docular
• md-page
• QCObjects
• and some others...

Installation

Download tarball

You can download the latest release tarball directly from [releases][releases]

Bower

bower install showdown

npm (server-side)

npm install showdown

NuGet package

PM> Install-Package showdownjs

The NuGet Packages can be found here.

CDN

You can also use one of several CDNs available:

• jsDelivr

  https://cdn.jsdelivr.net/npm/showdown@<version tag>/dist/showdown.min.js
  

• cdnjs

  https://cdnjs.cloudflare.com/ajax/libs/showdown/<version tag>/showdown.min.js
  

• unpkg

  https://unpkg.com/showdown/dist/showdown.min.js
  

Note: replace <version tag> with an actual full length version you're interested in e.g. 1.9.0

Browser Compatibility

Showdown has been tested successfully with:

• Firefox 1.5 and 2.0
• Chrome 12.0
• Internet Explorer 6 and 7
• Safari 2.0.4
• Opera 8.54 and 9.10
• Netscape 8.1.2
• Konqueror 3.5.4

In theory, Showdown will work in any browser that supports ECMA 262 3rd Edition (JavaScript 1.5). The converter itself might even work in things that aren't web browsers, like Acrobat. No promises.

Node compatibility

Showdown supports node versions in the "Current", "Active" and "Maintenance" phases. Currently this includes Node 12.x, 14.x, 16.x and 17.x. See the node release roadmap for more details.

Other versions of node may likely work, but they are not tested regularly.

Pervious versions

If you're looking for showdown v<1.0.0, you can find it in the [legacy branch][legacy-branch].

If you are looking for showdown 1.* you can find it in the [version_1.x][version_1.x] branch.

Changelog

You can check the full [changelog][changelog]

Extended documentation

Check our [wiki pages][wiki] for examples and a more in-depth documentation.

Quick Example

Node

Markdown to HTML

var showdown  = require('showdown'),
    converter = new showdown.Converter(),
    text      = '# hello, markdown!',
    html      = converter.makeHtml(text);

HTML to Markdown

var showdown  = require('showdown'),
    converter = new showdown.Converter(),
    html      = '<a href="https://patreon.com/showdownjs">Please Support us!</a>',
    md        = converter.makeMarkdown(text);

Browser

var converter = new showdown.Converter(),
    html      = converter.makeHtml('# hello, markdown!'),
    md        = converter.makeMd('<a href="https://patreon.com/showdownjs">Please Support us!</a>');

Output

Both examples should output...

    <h1 id="hellomarkdown">hello, markdown!</h1>

[Please Support us!](https://patreon.com/showdownjs)

Options

You can change some of showdown's default behavior through options.

Setting options

Options can be set:

Globally

Setting a "global" option affects all instances of showdown

showdown.setOption('optionKey', 'value');

Locally

Setting a "local" option only affects the specified Converter object. Local options can be set:

• through the constructor js var converter = new showdown.Converter({optionKey: 'value'});

• through the setOption() method js var converter = new showdown.Converter(); converter.setOption('optionKey', 'value');

Getting an option

Showdown provides 2 methods (both local and global) to retrieve previous set options.

getOption()

// Global
var myOption = showdown.getOption('optionKey');

//Local
var myOption = converter.getOption('optionKey');

getOptions()

// Global
var showdownGlobalOptions = showdown.getOptions();

//Local
var thisConverterSpecificOptions = converter.getOptions();

Retrieve the default options

You can get showdown's default options with:

var defaultOptions = showdown.getDefaultOptions();

Valid Options

• omitExtraWLInCodeBlocks: (boolean) [default false] Omit the trailing newline in a code block. Ex:

  This: html <code><pre>var foo = 'bar'; </pre></code> Becomes this: html <code><pre>var foo = 'bar';</pre></code>

• noHeaderId: (boolean) [default false] Disable the automatic generation of header ids. Setting to true overrides prefixHeaderId

• customizedHeaderId: (boolean) [default false] Use text in curly braces as header id. (since v1.7.0) Example: ## Sample header {real-id} will use real-id as id

• ghCompatibleHeaderId: (boolean) [default false] Generate header ids compatible with github style (spaces are replaced with dashes and a bunch of non alphanumeric chars are removed) (since v1.5.5)

• prefixHeaderId: (string/boolean) [default false] Add a prefix to the generated header ids. Passing a string will prefix that string to the header id. Setting to true will add a generic 'section' prefix.

• rawPrefixHeaderId: (boolean) [default false] Setting this option to true will prevent showdown from modifying the prefix. This might result in malformed IDs (if, for instance, the " char is used in the prefix). Has no effect if prefixHeaderId is set to false. (since v 1.7.3)

• rawHeaderId: (boolean) [default false] Remove only spaces, ' and " from generated header ids (including prefixes), replacing them with dashes (-). WARNING: This might result in malformed ids (since v1.7.3)

• parseImgDimensions: (boolean) [default false] Enable support for setting image dimensions from within markdown syntax. Examples: ![foo](foo.jpg =100x80) simple, assumes units are in px ![bar](bar.jpg =100x*) sets the height to "auto" ![baz](baz.jpg =80%x5em) Image with width of 80% and height of 5em

• headerLevelStart: (integer) [default 1] Set the header starting level. For instance, setting this to 3 means that

  ```md

  foo

  ``` will be parsed as

  html <h3>foo</h3>

• simplifiedAutoLink: (boolean) [default false] Turning this option on will enable automatic linking to urls. This means that:

md some text www.google.com will be parsed as ```html

some text www.google.com ```

• excludeTrailingPunctuationFromURLs: (boolean) [default false] This option excludes trailing punctuation from autolinking urls. Punctuation excluded: . ! ? ( ). Only applies if simplifiedAutoLink option is set to true.

md check this link www.google.com! will be parsed as ```html

check this link www.google.com!

```

• literalMidWordUnderscores: (boolean) [default false] Turning this on will stop showdown from interpreting underscores in the middle of words as <em> and <strong> and instead treat them as literal underscores.

Example:

md some text with__underscores__in middle will be parsed as ```html

some text with__underscores__in middle

```

• literalMidWordAsterisks: (boolean) [default false] Turning this on will stop showdown from interpreting asterisks in the middle of words as <em> and <strong> and instead treat them as literal asterisks.

Example:

md some text with**underscores**in middle will be parsed as ```html

some text withunderscoresin middle

```

• strikethrough: (boolean) [default false] Enable support for strikethrough syntax. ~~strikethrough~~ as <del>strikethrough</del>

• tables: (boolean) [default false] Enable support for tables syntax. Example:

md | h1 | h2 | h3 | |:------|:-------:|--------:| | 100 | [a][1] | ![b][2] | | *foo* | **bar** | ~~baz~~ |

See the wiki for more info

• tablesHeaderId: (boolean) [default false] If enabled adds an id property to table headers tags.

• ghCodeBlocks: (boolean) [default true] Enable support for GFM code block style.

• tasklists: (boolean) [default false] Enable support for GFM tasklists. Example:

md - [x] This task is done - [ ] This is still pending * smoothLivePreview: (boolean) [default false] Prevents weird effects in live previews due to incomplete input

• smartIndentationFix: (boolean) [default false] Tries to smartly fix indentation problems related to es6 template strings in the midst of indented code.

• disableForced4SpacesIndentedSublists: (boolean) [default false] Disables the requirement of indenting sublists by 4 spaces for them to be nested, effectively reverting to the old behavior where 2 or 3 spaces were enough. (since v1.5.0)

• simpleLineBreaks: (boolean) [default false] Parses line breaks as `

`, like GitHub does, without needing 2 spaces at the end of the line (since v1.5.1)

md a line wrapped in two

turns into:

```html

a line

wrapped in two

```

• requireSpaceBeforeHeadingText: (boolean) [default false] Makes adding a space between # and the header text mandatory (since v1.5.3)

• ghMentions: (boolean) [default false] Enables github @mentions, which link to the username mentioned (since v1.6.0)

• ghMentionsLink: (string) [default https://github.com/{u}] Changes the link generated by @mentions. Showdown will replace {u} with the username. Only applies if ghMentions option is enabled. Example: @tivie with ghMentionsOption set to //mysite.com/{u}/profile will result in <a href="https://github.com/showdownjs/showdown/raw/2.1.0/mysite.com/tivie/profile">@tivie</a>

• encodeEmails: (boolean) [default true] Enable e-mail addresses encoding through the use of Character Entities, transforming ASCII e-mail addresses into its equivalent decimal entities. (since v1.6.1)

NOTE: Prior to version 1.6.1, emails would always be obfuscated through dec and hex encoding.

• openLinksInNewWindow: (boolean) [default false] Open all links in new windows (by adding the attribute target="_blank" to <a> tags) (since v1.7.0)

• backslashEscapesHTMLTags: (boolean) [default false] Support for HTML Tag escaping. ex: `\

foo\

` (since v1.7.2)

• emoji: (boolean) [default false] Enable emoji support. Ex: this is a :smile: emoji For more info on available emojis, see https://github.com/showdownjs/showdown/wiki/Emojis (since v.1.8.0)

• underline: (boolean) [default false] EXPERIMENTAL FEATURE Enable support for underline. Syntax is double or triple underscores ex: __underlined word__. With this option enabled, underscores are no longer parses into <em> and <strong>.

• ellipsis: (boolean) [default true] Replaces three dots with the ellipsis unicode character.

• completeHTMLDocument: (boolean) [default false] Outputs a complete html document, including <html>, <head> and <body> tags' instead of an HTML fragment. (since v.1.8.5)

• metadata: (boolean) [default false] Enable support for document metadata (defined at the top of the document between ««« and »»» or between --- and ---). (since v.1.8.5)

js var conv = new showdown.Converter({metadata: true}); var html = conv.makeHtml(someMd); var metadata = conv.getMetadata(); // returns an object with the document metadata

• splitAdjacentBlockquotes: (boolean) [default false] Split adjacent blockquote blocks.(since v.1.8.6)

NOTE: Please note that until version 1.6.0, all of these options are DISABLED by default in the cli tool.

Flavors

You can also use flavors or presets to set the correct options automatically, so that showdown behaves like popular markdown flavors.

Currently, the following flavors are available:

• original - original markdown flavor as in John Gruber's spec
• vanilla - showdown bas