!!! warning ""
Starting from the version 1.6.0
and earlier, all the options are disabled
by default in the cli tool.
Support escaping of HTML tags.
- type:
boolean
- default value:
false
- introduced in:
1.7.2
=== "input"
```html
\<div>foo\</div>
```
=== "output (value is true
)"
```html
<p><div>foo</div></p>
```
Output a complete HTML document, including <html>
, <head>
, and <body>
tags instead of an HTML fragment.
- type:
boolean
- default value:
false
- introduced in:
1.8.5
Set custom ID for a heading.
!!! warning ""
This option can be overridden with the noHeaderId
option.
- type:
boolean
- default value:
false
- introduced in:
1.7.0
=== "code"
```html
## Sample heading {mycustomid}
```
=== "output"
```html
<h1 id="mycustomid">This is a heading</h1>
```
!!! hint ""
For better readability and human-friendliness of the heading IDs, it is also recommended to set the ghCompatibleHeaderId
option to true
.
Disable the rule of 4 spaces to indent sub-lists. If enabled, this option effectively reverts to the old behavior where you can indent sub-lists with 2 or 3 spaces.
- type:
boolean
- default value:
false
- introduced in:
1.5.0
=== "input"
```
- one
- two
...
- one
- two
```
=== "output (value is false
)"
```html
<ul>
<li>one</li>
<li>two</li>
</ul>
<p>...</p>
<ul>
<li>one
<ul>
<li>two</li>
</ul>
</li>
</ul>
```
=== "output (value is true
)"
```html
<ul>
<li>one
<ul>
<li>two</li>
</ul>
</li>
</ul>
<p>...</p>
<ul>
<li>one
<ul>
<li>two</li>
</ul>
</li>
</ul>
```
Enable emoji support. For more info on available emojis, see https://github.com/showdownjs/showdown/wiki/Emojis (since v.1.8.0)
- type:
boolean
- default value:
false
- introduced in:
1.8.0
=== "input"
```
this is a :smile: emoji
```
=== "output (value is false
)"
```html
<p>this is a :smile: emoji</p>
```
=== "output (value is true
)"
```html
<p>this is a 😄 emoji</p>
```
!!! hint "Full list of supported emojies"
Check the [Showdown Wiki](https://github.com/showdownjs/showdown/wiki/Emojis#emoji-list) for a full list of supported emojies.
Enable automatic obfuscation of email addresses. During this process, email addresses are encoded via Character Entities, transforming ASCII email addresses into their equivalent decimal entities.
- type:
boolean
- default value:
false
- introduced in:
1.6.1
=== "input"
```
<myself@example.com>
```
=== "output (value is false
)"
```html
<a href="mailto:myself@example.com">myself@example.com</a>
```
=== "output (value is true
)"
```html
<a href="mailto:myself@example.com">myself@example.com</a>
```
Exclude trailing punctuation from autolinked URLs: .
!
?
(
)
This option applies only to links generated by simplifiedAutoLink
.
- type:
boolean
- default value:
false
- introduced in:
1.5.1
=== "input"
```
check this link www.google.com.
```
=== "output (value is false
)"
```html
<p>check this link <a href="www.google.com">www.google.com.</a></p>
```
=== "output (value is true
)"
```html
<p>check this link <a href="www.google.com">www.google.com</a>.</p>
```
Enable support for GFM code block style syntax (fenced codeblocks).
- type:
boolean
- default value:
true
- introduced in:
0.3.1
=== "example"
```
```
some code here
```
```
Generate heading IDs compatible with GitHub style: spaces are replaced with dashes, and certain non-alphanumeric chars are removed.
!!! warning ""
This option can be overridden with the noHeaderId
option.
- type:
boolean
- default value:
false
- introduced in:
1.5.5
=== "input"
```
# This is a heading with @#$%
```
=== "output (value is false
)"
```html
<h1 id="thisisaheading">This is a heading</h1>
```
=== "output (value is true
)"
```html
<h1 id="this-is-a-heading-with-">This is a heading with @#$%</h1>
```
Enables support for GitHub @mentions
that allows you to link to the GitHub profile page of the mentioned username.
- type:
boolean
- default value:
false
- introduced in:
1.6.0
=== "input"
```
hello there @tivie
```
=== "output (value is false
)"
```html
<p>hello there @tivie</p>
```
=== "output (value is true
)"
```html
<p>hello there <a href="https://www.github.com/tivie">@tivie</a></p>
```
Specify where the link generated by @mentions
should point to. Works only when ghMentions: true
.
- type:
boolean
- default value:
https://github.com/{u}
- introduced in:
1.6.2
=== "input"
```
hello there @tivie
```
=== "output (value is https://github.com/{u}
)"
```html
<p>hello there <a href="https://www.github.com/tivie">@tivie</a></p>
```
=== "output (value is http://mysite.com/{u}/profile
)"
```html
<p>hello there <a href="//mysite.com/tivie/profile">@tivie</a></p>
```
Set starting level for the heading tags.
- type:
integer
- default value:
1
- introduced in:
1.1.0
=== "input"
```
# This is a heading
```
=== "output (value is 1
)"
```html
<h1>This is a heading</h1>
```
=== "output (value is 3
)"
```html
<h3>This is a heading</h3>
```
Treat underscores in the middle of words as literal characters.
Underscores allow you to specify the words that should be emphasized. However, in some cases, this may be unwanted behavior. With this option enabled, underscores in the middle of words will no longer be interpreted as <em>
and <strong>
, but as literal underscores.
- type:
boolean
- default value:
false
- introduced in:
1.2.0
=== "input"
```
some text with__underscores__in the middle
```
=== "output (value is false
)"
```html
<p>some text with<strong>underscores</strong>in the middle</p>
```
=== "output (value is true
)"
```html
<p>some text with__underscores__in the middle</p>
```
Enable support for document metadata (front-matter). You can define metadata at the top of a document between ««« »»»
or --- ---
symbols.
- type:
boolean
- default value:
false
- introduced in:
1.8.5
=== "input"
```js
let ref = `referenced value`;
var markdown = `
---
first: Lorem
second: Ipsum
ref_variable: ${ref}
---
`
var conv = new showdown.Converter({metadata: true});
var html = conv.makeHtml(markdown);
var metadata = conv.getMetadata();
```
=== "output (value is true
)"
```js
// console.log(metadata)
{
first: 'Lorem',
second: 'Ipsum',
ref_variable: 'referenced value'
}
```
Disable automatic generation of heading IDs.
!!! warning ""
Setting the option to true
overrides the following options:
* [`prefixHeaderId`](#prefixheaderid)
* [`customizedHeaderId`](#customizedheaderid)
* [`ghCompatibleHeaderId`](#ghcompatibleheaderid)
- type:
boolean
- default value:
false
- introduced in:
1.1.0
=== "input"
```
# This is a heading
```
=== "output (value is false
)"
```html
<h1 id="thisisaheading">This is a heading</h1>
```
=== "output (value is true
)"
```html
<h1>This is a heading</h1>
```
Omit trailing newline in code blocks (which is set by default before the closing tag). This option affects both indented and fenced (gfm style) code blocks.
- type:
boolean
- default value:
false
- introduced in:
1.0.0
=== "input"
```
var foo = 'bar';
```
=== "output (value is false
)"
```html
<code><pre>var foo = 'bar';
</pre></code>
```
=== "output (value is true
)"
```html
<code><pre>var foo = 'bar';</pre></code>
```
Open links in new windows.
- type:
boolean
- default value:
false
- introduced in:
1.7.0
=== "input"
```
[link](https://google.com)
```
=== "output (value is false
)"
```html
<a href="https://google.com">link</a>
```
=== "output (value is true
)"
```html
<a href="https://google.com" rel="noopener noreferrer" target="_blank">link</a>
```
Set image dimensions from within Markdown syntax.
- type:
boolean
- default value:
false
- introduced in:
1.1.0
=== "example"
```
 set width to 100px and height to 80px
 set width to 100px and height to "auto"
 set width to 80% and height to 5em
```
Add a prefix to the generated heading ID:
- Passing a string will add that string to the heading ID.
- Passing
true
will add a genericsection
prefix.
!!! warning ""
This option can be overridden with the noHeaderId
option.
- type:
string / boolean
- default value:
false
=== "input"
```
# This is a heading
```
=== "output (value is false
)"
```html
<h1 id="thisisaheading">This is a heading</h1>
```
=== "output (value is true
)"
```html
<h1 id="sectionthisisaheading">This is a heading</h1>
```
=== "output (value is showdown
)"
```html
<h1 id="showdownthisisaheading">This is a heading</h1>
```
Replace
(space), '
(single quote), and "
(double quote) with -
(dash) in the generated heading IDs, including prefixes.
!!! danger "" Use with caution as it might result in malformed IDs.
- type:
- default value:
- introduced in:
1.7.3
Prevent Showndown from modifying the prefix. Works only when prefixHeaderId
is set to a string value.
!!! danger ""
Use with caution as it might result in malformed IDs. For example, when the prefix contains special characters like "
\
/
or others.
- type:
boolean
- default value:
false
- introduced in:
1.7.3
Require a space between a heading #
and the heading text.
- type:
boolean
- default value:
false
- introduced in:
1.5.3
=== "input"
```
#heading
```
=== "output (value is false
)"
```html
<h1 id="heading">heading</h1>
```
=== "output (value is true
)"
```html
<p>#heading</p>
```
Parse line breaks as <br/>
in paragraphs (GitHub-style behavior).
- type:
boolean
- default value:
false
- introduced in:
1.5.1
=== "input"
```
a line
wrapped in two
```
=== "output (value is false
)"
```html
<p>a line
wrapped in two</p>
```
=== "output (value is true
)"
```html
<p>a line<br>
wrapped in two</p>
```
Enable automatic linking for plain text URLs.
- type:
boolean
- default value:
false
- introduced in:
1.2.0
=== "input"
```
Lorem ipsum www.google.com
```
=== "output (value is false
)"
```html
<p>Lorem ipsum www.google.com</p>
```
=== "output (value is true
)"
```html
<p>Lorem ipsum <a href="www.google.com">www.google.com</a></p>
```
Resolve indentation problems related to ES6 template strings in the midst of indented code.
- type:
boolean
- default value:
false
- introduced in:
1.4.2
Resolve an awkward effect when a paragraph is followed by a list. This effect appears on some circumstances, in live preview editors.
- type:
boolean
- default value:
false
- introduced in:
1.2.1
!!! example "awkward effect"

Split adjacent blockquote blocks.
- type:
boolean
- default value:
false
- introduced in:
1.8.6
=== "input"
```
> Quote #1
>> Sub-quote 1
> Quote #2
>> Sub-quote 2
```
=== "output (value is false
)"
```html
<blockquote>
<p>Quote #1</p>
<blockquote>
<p>Sub-quote 1</p>
</blockquote>
<p>Quote #2</p>
<blockquote>
<p>Sub-quote 2</p>
</blockquote>
</blockquote>
```
=== "output (value is true
)"
```html
<blockquote>
<p>Quote #1</p>
<blockquote>
<p>Sub-quote 1</p>
</blockquote>
</blockquote>
<blockquote>
<p>Quote #2</p>
<blockquote>
<p>Sub-quote 2</p>
</blockquote>
</blockquote>
```
Enable support for strikethrough (<del>
).
- type:
boolean
- default value:
false
- introduced in:
1.2.0
=== "input"
```
~~strikethrough~~
```
=== "output (value is true
)"
```html
<del>strikethrough</del>
```
Enable support for tables syntax.
- type:
boolean
- default value:
false
- introduced in:
1.2.0
=== "example"
```
| h1 | h2 | h3 |
|:------|:-------:|--------:|
| 100 | [a][1] | ![b][2] |
| *foo* | **bar** | ~~baz~~ |
```
Generate automatic IDs for table headings. Works only when tables: true
.
- type:
boolean
- default value:
false
- introduced in:
1.2.0
Enable support for GitHub style tasklists.
- type:
boolean
- default value:
false
- introduced in:
1.2.0
=== "example"
```
- [x] This task is done
- [ ] This task is still pending
```
Enable support for underline. If enabled, underscores will no longer be parsed as <em>
and <strong>
.
- type:
boolean
- default value:
false
- status:
Experimental
=== "example"
```
__underlined word__ // double underscores
___underlined word___ // triple underscores
```