markdown.html

<p align="center"><b>Markdownフォーマットを使用してウェブページを書く</b></p>

<p>(このテキストは、<a target="_blank" href="http://daringfireball.net/projects/markdown/syntax">the original Markdown syntax page</a>)のコピーです。</p>

<hr />
<div id="Main">

<div class="article">

<ul>

<li><a href="#overview">概要</a>

<ul>

<li><a href="#philosophy">理念</a></li>

<li><a href="#html">インラインHTML</a></li>

<li><a href="#autoescape">スペシャルキャラクタの自動エスケープ</a></li>

</ul></li>

<li><a href="#block">ブロック要素</a>

<ul>

<li><a href="#p">段落と改行</a></li>

<li><a href="#header">ヘッダ</a></li>

<li><a href="#blockquote">引用</a></li>

<li><a href="#list">リストアイテム</a></li>

<li><a href="#precode">コード</a></li>

<li><a href="#hr">水平線</a></li>

</ul></li>

<li><a href="#span">汎用的なインライン要素</a>

<ul>

<li><a href="#link">リンク</a></li>

<li><a href="#em">強調</a></li>

<li><a href="#code">コード</a></li>

<li><a href="#img">イメージ</a></li>

</ul></li>

<li><a href="#misc">その他</a>

<ul>

<li><a href="#backslash">バックシュラッシュエスケープ</a></li>

<li><a href="#autolink">自動リンク</a></li>

</ul></li>

</ul>

<hr />

<h2 id="overview">概要</h2>

<h3 id="philosophy">理念</h3>

<p>Markdownは、可能な限り簡単に読み、簡単に書くことを目的としています。</p>

<p>しかしながら、何にもまして読みやすいことが重要視されています。
Markdownフォーマットドキュメントは、タグによるマークアップやフォーマットインストラクション無しに、プレインテキストとしてそのまま公開されます。
Markdownのシンタックスは、
<a href="http://docutils.sourceforge.net/mirror/setext.html">Setext</a>、
<a href="http://www.aaronsw.com/2002/atx/">atx</a>、
<a href="http://textism.com/tools/textile/">Textile</a>、
<a href="http://docutils.sourceforge.net/rst.html">reStructuredText</a>、
<a href="http://www.triptico.com/software/grutatxt.html">Grutatext</a>、
<a href="http://ettext.taint.org/doc/">EtText</a>
を含む幾つかのテキストtoHTMLフィルタに影響を受けました。
しかし、Markdownのシンタックスの一番大きなインスピレーションの源は、プレインテキストメールのフォーマットです。
</p>

<p>このため、Markdownのシンタックスは、完全に句読記号文字から成ります。句読記号文字は、それらが意味するとおりに見えるように慎重に選ばれました。
例えば、言葉の周りのアスタリスクは実際には*強調*のように見えます。Markdownではリストとして表示されます。
あなたがメールを使用したことがあると仮定して、blockquotes(引用)は引用されたテキストのように見えます。
</p>

<h3 id="html">インラインHTML</h3>

<p>Markdownのシンタックスは、1つの事柄を目的としています: ウェブを<em>記述</em>するようなフォーマットとして使用する。</p>

<p>Markdownは、HTMLの代替物ではなく、むしろHTMLに近いと言えます。
シンタックスは非常にコンパクトで、HTMLタグの非常に小さなサブセットのみと一致します。
Markdownのアイディアは、HTMLタグを簡単に挿入できるシンタックスを作成することでは<em>ありません</em>。
私の見解として、HTMLタグは既に簡単に挿入することができるからです。
Markdownのアイディアは、簡単に読め、簡単に書け、散文的に編集できることにあります。
HTMLは<em>出版するための</em>フォーマットです。これに対して、Markdownは<em>書くための</em>フォーマットです。
従って、Markdownフォーマットシンタックスは、プレインテキストで表現することのみに重点を置いています。</p>

<p>Markdownシンタックスで表現できないマークアップには、単純にHTMLそのものを使用できます。
MarkdownからHTMLに切り替える場合、事前に記したり、区切り文字を入れる必要はありません。タグを使用するだけです。</p>

<p>唯一の制限事項は、ブロック要素を使用する場合です - 例 <code>&lt;div&gt;</code>、<code>&lt;table&gt;</code>、<code>&lt;pre&gt;</code>、<code>&lt;p&gt;</code>等
 - これらは空白行で囲まれたコンテンツで分離する必要があります。また、開始および終了タグはタブまた空白でインデントしてはいけません。
Markdownは、余分(不必要)な<code>&lt;p&gt;</code>タグをブロック要素の周囲に追加することはありません。</p>

<p>例えば、HTMLテーブルをMarkdown記事に追加する場合:</p>

<pre><code>これは通常の段落です。

&lt;table&gt;

    &lt;tr&gt;

        &lt;td&gt;Foo&lt;/td&gt;

    &lt;/tr&gt;

&lt;/table&gt;

これはもう1つの通常の段落です。

</code></pre>


<p>注意: Markdownフォーマットシンタックスはブロック要素の中では処理されません 
例、あなたはMarkdown-style <code>*強調*</code> をHTMLブロックの中で使用できません。</p>

<p>汎用的なインライン要素 - 例 <code>&lt;span&gt;</code>、<code>&lt;cite&gt;</code>、<code>&lt;del&gt;</code> - は、
Markdown段落、リスト、ヘッダのどこでも使用することができます。あなたが希望する場合、Markdownフォーマットの
代わりにHTMLタグを使用することもできます。例えば、HTMLの<code>&lt;a&gt;</code>または<code>&lt;img&gt;</code>タグをMarkdown
のリンクやイメージのシンタックスの代わりに使用できます。</p>

<p>HTMLのブロック要素と異なり、Markdownシンタックスは汎用的なインライン要素の中でも処理<em>されます</em>。</p>

<h3 id="autoescape">スペシャルキャラクタの自動エスケープ</h3>

<p>HTMLには特別に扱う必要のある2つの文字があります: <code>&lt;</code> と <code>&amp;</code>です。左鍵括弧タグの開始に使用し、アンパサンドはHTMLエンティティーを示すために使用します。
これらの文字を使用する場合は、エンティティーとしてエスケープする必要があります。例、<code>&amp;lt;</code> と <code>&amp;amp;</code>です。</p>

<p>特にアンパサンドは、ホームページ製作者泣かせの存在です。&#8216;AT&amp;T&#8217;と書きたい場合、&#8216;<code>AT&amp;amp;T</code>&#8217;と書く必要があります。
更に、URLの中でもアンパサンドをエスケープする必要があります。従って、次のようにリンクしたい場合:</p>

<pre><code>http://images.google.com/images?num=30&amp;q=larry+bird

</code></pre>

<p>アンカータグ<code>href</code>の属性において、URLを次のようにエンコードする必要があります:</p>

<pre><code>http://images.google.com/images?num=30&amp;amp;q=larry+bird

</code></pre>

<p>言うまでもなく、このことは忘れやすく、恐らく適切にマークアップされたウェブサイトでHTML妥当性エラーが発生する最も一般的な原因となっています。</p>

<p>Markdownは必要に応じてエスケープ処理を行いますので、あなたはこれらの文字を自然に使うことができます。
アンパサンドをHTMLエンティティーの一部として使用したい場合は、そのままの状態にされます。そうで無い場合は、<code>&amp;amp;</code>にエンコードされます。</p>

<p>ですから、あなたが著作権記号を記事に入れたい場合は、次のように記述できます:</p>

<pre><code>&amp;copy;

</code></pre>

<p>Markdownはアンパサンドをそのままにします。しかし、次のように記述すると:</p>

<pre><code>AT&amp;T

</code></pre>

<p>Markdownは次のようにエンコードします:</p>

<pre><code>AT&amp;amp;T

</code></pre>

<p>同様に、Markdownは<a href="#html">inline HTML</a>をサポートします。鍵括弧をHTMLの区切り文字として使用する場合、Markdownは鍵括弧をそのままにします。しかし、次のように記述すると:</p>

<pre><code>4 &lt; 5

</code></pre>

<p>Markdownは次のようにエンコードします:</p>

<pre><code>4 &amp;lt; 5

</code></pre>

<p>しかし、Markdownコードspansとblocksの中では、鍵括弧、アンパサンドは<em>常に</em>自動的にエンコードされます。このことにより、Markdownを使用すると簡単にHTMLコードを記述することができます。
(逆に、生のHTMLでHTMLシンタックスを記述すると酷いことになります。あなたのサンプルコード内の全ての <code>&lt;</code> と <code>&amp;</code> をエスケープする必要があるからです。)</p>

<hr />

<h2 id="block">ブロック要素</h2>

<h3 id="p">段落と改行</h3>

<p>A paragraph is simply one or more consecutive lines of text, separated

by one or more blank lines. (A blank line is any line that looks like a

blank line &#8212; a line containing nothing but spaces or tabs is considered

blank.) Normal paragraphs should not be intended with spaces or tabs.</p>



<p>The implication of the &#8220;one or more consecutive lines of text&#8221; rule is

that Markdown supports &#8220;hard-wrapped&#8221; text paragraphs. This differs

significantly from most other text-to-HTML formatters (including Movable

Type&#8217;s &#8220;Convert Line Breaks&#8221; option) which translate every line break

character in a paragraph into a <code>&lt;br /&gt;</code> tag.</p>



<p>When you <em>do</em> want to insert a <code>&lt;br /&gt;</code> break tag using Markdown, you

end a line with two or more spaces, then type return.</p>



<p>Yes, this takes a tad more effort to create a <code>&lt;br /&gt;</code>, but a simplistic

&#8220;every line break is a <code>&lt;br /&gt;</code>&#8221; rule wouldn&#8217;t work for Markdown.

Markdown&#8217;s email-style <a href="#blockquote">blockquoting</a> and multi-paragraph <a href="#list">list items</a>

work best &#8212; and look better &#8212; when you format them with hard breaks.</p>



<h3 id="header">ヘッダ</h3>



<p>Markdown supports two styles of headers, <a href="http://docutils.sourceforge.net/mirror/setext.html">Setext</a> and <a href="http://www.aaronsw.com/2002/atx/">atx</a>.</p>



<p>Setext-style headers are &#8220;underlined&#8221; using equal signs (for first-level

headers) and dashes (for second-level headers). For example:</p>



<pre><code>This is an H1

=============



This is an H2

-------------

</code></pre>



<p>Any number of underlining <code>=</code>&#8217;s or <code>-</code>&#8217;s will work.</p>



<p>Atx-style headers use 1-6 hash characters at the start of the line,

corresponding to header levels 1-6. For example:</p>



<pre><code># This is an H1



## This is an H2



###### This is an H6

</code></pre>



<p>Optionally, you may &#8220;close&#8221; atx-style headers. This is purely

cosmetic &#8212; you can use this if you think it looks better. The

closing hashes don&#8217;t even need to match the number of hashes

used to open the header. (The number of opening hashes

determines the header level.) :</p>



<pre><code># This is an H1 #



## This is an H2 ##



### This is an H3 ######

</code></pre>



<h3 id="blockquote">引用</h3>



<p>Markdown uses email-style <code>&gt;</code> characters for blockquoting. If you&#8217;re

familiar with quoting passages of text in an email message, then you

know how to create a blockquote in Markdown. It looks best if you hard

wrap the text and put a <code>&gt;</code> before every line:</p>



<pre><code>&gt; This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet,

&gt; consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus.

&gt; Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus.

&gt; 

&gt; Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse

&gt; id sem consectetuer libero luctus adipiscing.

</code></pre>



<p>Markdown allows you to be lazy and only put the <code>&gt;</code> before the first

line of a hard-wrapped paragraph:</p>



<pre><code>&gt; This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet,

consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus.

Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus.



&gt; Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse

id sem consectetuer libero luctus adipiscing.

</code></pre>



<p>Blockquotes can be nested (i.e. a blockquote-in-a-blockquote) by

adding additional levels of <code>&gt;</code>:</p>



<pre><code>&gt; This is the first level of quoting.

&gt;

&gt; &gt; This is nested blockquote.

&gt;

&gt; Back to the first level.

</code></pre>



<p>Blockquotes can contain other Markdown elements, including headers, lists,

and code blocks:</p>



<pre><code>&gt; ## This is a header.

&gt; 

&gt; 1.   This is the first list item.

&gt; 2.   This is the second list item.

&gt; 

&gt; Here's some example code:

&gt; 

&gt;     return shell_exec("echo $input | $markdown_script");

</code></pre>



<p>Any decent text editor should make email-style quoting easy. For

example, with BBEdit, you can make a selection and choose Increase

Quote Level from the Text menu.</p>



<h3 id="list">Lists</h3>



<p>Markdown supports ordered (numbered) and unordered (bulleted) lists.</p>



<p>Unordered lists use asterisks, pluses, and hyphens &#8212; interchangably

&#8212; as list markers:</p>



<pre><code>*   Red

*   Green

*   Blue

</code></pre>



<p>is equivalent to:</p>



<pre><code>+   Red

+   Green

+   Blue

</code></pre>



<p>and:</p>



<pre><code>-   Red

-   Green

-   Blue

</code></pre>



<p>Ordered lists use numbers followed by periods:</p>



<pre><code>1.  Bird

2.  McHale

3.  Parish

</code></pre>



<p>It&#8217;s important to note that the actual numbers you use to mark the

list have no effect on the HTML output Markdown produces. The HTML

Markdown produces from the above list is:</p>



<pre><code>&lt;ol&gt;

&lt;li&gt;Bird&lt;/li&gt;

&lt;li&gt;McHale&lt;/li&gt;

&lt;li&gt;Parish&lt;/li&gt;

&lt;/ol&gt;

</code></pre>



<p>If you instead wrote the list in Markdown like this:</p>



<pre><code>1.  Bird

1.  McHale

1.  Parish

</code></pre>



<p>or even:</p>



<pre><code>3. Bird

1. McHale

8. Parish

</code></pre>



<p>you&#8217;d get the exact same HTML output. The point is, if you want to,

you can use ordinal numbers in your ordered Markdown lists, so that

the numbers in your source match the numbers in your published HTML.

But if you want to be lazy, you don&#8217;t have to.</p>



<p>If you do use lazy list numbering, however, you should still start the

list with the number 1. At some point in the future, Markdown may support

starting ordered lists at an arbitrary number.</p>



<p>List markers typically start at the left margin, but may be indented by

up to three spaces. List markers must be followed by one or more spaces

or a tab.</p>



<p>To make lists look nice, you can wrap items with hanging indents:</p>



<pre><code>*   Lorem ipsum dolor sit amet, consectetuer adipiscing elit.

    Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi,

    viverra nec, fringilla in, laoreet vitae, risus.

*   Donec sit amet nisl. Aliquam semper ipsum sit amet velit.

    Suspendisse id sem consectetuer libero luctus adipiscing.

</code></pre>



<p>But if you want to be lazy, you don&#8217;t have to:</p>



<pre><code>*   Lorem ipsum dolor sit amet, consectetuer adipiscing elit.

Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi,

viverra nec, fringilla in, laoreet vitae, risus.

*   Donec sit amet nisl. Aliquam semper ipsum sit amet velit.

Suspendisse id sem consectetuer libero luctus adipiscing.

</code></pre>



<p>If list items are separated by blank lines, Markdown will wrap the

items in <code>&lt;p&gt;</code> tags in the HTML output. For example, this input:</p>



<pre><code>*   Bird

*   Magic

</code></pre>



<p>will turn into:</p>



<pre><code>&lt;ul&gt;

&lt;li&gt;Bird&lt;/li&gt;

&lt;li&gt;Magic&lt;/li&gt;

&lt;/ul&gt;

</code></pre>



<p>But this:</p>



<pre><code>*   Bird



*   Magic

</code></pre>



<p>will turn into:</p>



<pre><code>&lt;ul&gt;

&lt;li&gt;&lt;p&gt;Bird&lt;/p&gt;&lt;/li&gt;

&lt;li&gt;&lt;p&gt;Magic&lt;/p&gt;&lt;/li&gt;

&lt;/ul&gt;

</code></pre>



<p>List items may consist of multiple paragraphs. Each subsequent

paragraph in a list item must be intended by either 4 spaces

or one tab:</p>



<pre><code>1.  This is a list item with two paragraphs. Lorem ipsum dolor

    sit amet, consectetuer adipiscing elit. Aliquam hendrerit

    mi posuere lectus.



    Vestibulum enim wisi, viverra nec, fringilla in, laoreet

    vitae, risus. Donec sit amet nisl. Aliquam semper ipsum

    sit amet velit.



2.  Suspendisse id sem consectetuer libero luctus adipiscing.

</code></pre>



<p>It looks nice if you indent every line of the subsequent

paragraphs, but here again, Markdown will allow you to be

lazy:</p>



<pre><code>*   This is a list item with two paragraphs.



    This is the second paragraph in the list item. You're

only required to indent the first line. Lorem ipsum dolor

sit amet, consectetuer adipiscing elit.



*   Another item in the same list.

</code></pre>



<p>To put a blockquote within a list item, the blockquote&#8217;s <code>&gt;</code>

delimiters need to be indented:</p>



<pre><code>*   A list item with a blockquote:



    &gt; This is a blockquote

    &gt; inside a list item.

</code></pre>



<p>To put a code block within a list item, the code block needs

to be indented <em>twice</em> &#8212; 8 spaces or two tabs:</p>



<pre><code>*   A list item with a code block:



        &lt;code goes here&gt;

</code></pre>



<p>It&#8217;s worth noting that it&#8217;s possible to trigger an ordered list by

accident, by writing something like this:</p>



<pre><code>1986. What a great season.

</code></pre>



<p>In other words, a <em>number-period-space</em> sequence at the beginning of a

line. To avoid this, you can backslash-escape the period:</p>



<pre><code>1986\. What a great season.

</code></pre>



<h3 id="precode">Code Blocks</h3>



<p>Pre-formatted code blocks are used for writing about programming or

markup source code. Rather than forming normal paragraphs, the lines

of a code block are interpreted literally. Markdown wraps a code block

in both <code>&lt;pre&gt;</code> and <code>&lt;code&gt;</code> tags.</p>



<p>To produce a code block in Markdown, simply indent every line of the

block by at least 4 spaces or 1 tab. For example, given this input:</p>



<pre><code>This is a normal paragraph:



    This is a code block.

</code></pre>



<p>Markdown will generate:</p>



<pre><code>&lt;p&gt;This is a normal paragraph:&lt;/p&gt;



&lt;pre&gt;&lt;code&gt;This is a code block.

&lt;/code&gt;&lt;/pre&gt;

</code></pre>



<p>One level of indentation &#8212; 4 spaces or 1 tab &#8212; is removed from each

line of the code block. For example, this:</p>



<pre><code>Here is an example of AppleScript:



    tell application "Foo"

        beep

    end tell

</code></pre>



<p>will turn into:</p>



<pre><code>&lt;p&gt;Here is an example of AppleScript:&lt;/p&gt;



&lt;pre&gt;&lt;code&gt;tell application "Foo"

    beep

end tell

&lt;/code&gt;&lt;/pre&gt;

</code></pre>



<p>A code block continues until it reaches a line that is not indented

(or the end of the article).</p>



<p>Within a code block, ampersands (<code>&amp;</code>) and angle brackets (<code>&lt;</code> and <code>&gt;</code>)

are automatically converted into HTML entities. This makes it very

easy to include example HTML source code using Markdown &#8212; just paste

it and indent it, and Markdown will handle the hassle of encoding the

ampersands and angle brackets. For example, this:</p>



<pre><code>    &lt;div class="footer"&gt;

        &amp;copy; 2004 Foo Corporation

    &lt;/div&gt;

</code></pre>



<p>will turn into:</p>



<pre><code>&lt;pre&gt;&lt;code&gt;&amp;lt;div class="footer"&amp;gt;

    &amp;amp;copy; 2004 Foo Corporation

&amp;lt;/div&amp;gt;

&lt;/code&gt;&lt;/pre&gt;

</code></pre>



<p>Regular Markdown syntax is not processed within code blocks. E.g.,

asterisks are just literal asterisks within a code block. This means

it&#8217;s also easy to use Markdown to write about Markdown&#8217;s own syntax.</p>



<h3 id="hr">Horizontal Rules</h3>



<p>You can produce a horizontal rule tag (<code>&lt;hr /&gt;</code>) by placing three or

more hyphens or asterisks on a line by themselves. If you wish, you

may use spaces between the hyphens or asterisks. Each of the following

lines will produce a horizontal rule:</p>



<pre><code>* * *



***



*****



- - -



---------------------------------------

</code></pre>



<hr />



<h2 id="span">Span Elements</h2>



<h3 id="link">Links</h3>



<p>Markdown supports two style of links: <em>inline</em> and <em>reference</em>.</p>



<p>In both styles, the link text is delimited by [square brackets].</p>



<p>To create an inline link, use a set of regular parentheses immediately

after the link text&#8217;s closing square bracket. Inside the parentheses,

put the URL where you want the link to point, along with an <em>optional</em>

title for the link, surrounded in quotes. For example:</p>



<pre><code>This is [an example](http://example.com/ "Title") inline link.



[This link](http://example.net/) has no title attribute.

</code></pre>



<p>Will produce:</p>



<pre><code>&lt;p&gt;This is &lt;a href="http://example.com/" title="Title"&gt;

an example&lt;/a&gt; inline link.&lt;/p&gt;



&lt;p&gt;&lt;a href="http://example.net/"&gt;This link&lt;/a&gt; has no

title attribute.&lt;/p&gt;

</code></pre>



<p>If you&#8217;re referring to a local resource on the same server, you can

use relative paths:</p>



<pre><code>See my [About](/about/) page for details.

</code></pre>



<p>Reference-style links use a second set of square brackets, inside

which you place a label of your choosing to identify the link:</p>



<pre><code>This is [an example][id] reference-style link.

</code></pre>



<p>You can optionally use a space to separate the sets of brackets:</p>



<pre><code>This is [an example] [id] reference-style link.

</code></pre>



<p>Then, anywhere in the document, you define your link label like this,

on a line by itself:</p>



<pre><code>[id]: http://example.com/  "Optional Title Here"

</code></pre>



<p>That is:</p>



<ul>

<li>Square brackets containing the link identifier (optionally

indented from the left margin using spaces or tabs);</li>

<li>followed by a colon;</li>

<li>followed by one or more spaces (or tabs);</li>

<li>followed by the URL for the link;</li>

<li>optionally followed by a title attribute for the link, enclosed

in double or single quotes.</li>

</ul>



<p>The link URL may, optionally, be surrounded by angle brackets:</p>



<pre><code>[id]: &lt;http://example.com/&gt;  "Optional Title Here"

</code></pre>



<p>You can put the title attribute on the next line and use extra spaces

or tabs for padding, which tends to look better with longer URLs:</p>



<pre><code>[id]: http://example.com/longish/path/to/resource/here

    "Optional Title Here"

</code></pre>



<p>Link definitions are only used for creating links during Markdown

processing, and are stripped from your document in the HTML output.</p>



<p>Link definition names may constist of letters, numbers, spaces, and punctuation &#8212; but they are <em>not</em> case sensitive. E.g. these two links:</p>



<pre><code>[link text][a]

[link text][A]

</code></pre>



<p>are equivalent.</p>



<p>The <em>implicit link name</em> shortcut allows you to omit the name of the

link, in which case the link text itself is used as the name.

Just use an empty set of square brackets &#8212; e.g., to link the word

&#8220;Google&#8221; to the google.com web site, you could simply write:</p>



<pre><code>[Google][]

</code></pre>



<p>And then define the link:</p>



<pre><code>[Google]: http://google.com/

</code></pre>



<p>Because link names may contain spaces, this shortcut even works for

multiple words in the link text:</p>



<pre><code>Visit [Daring Fireball][] for more information.

</code></pre>



<p>And then define the link:</p>



<pre><code>[Daring Fireball]: http://daringfireball.net/

</code></pre>



<p>Link definitions can be placed anywhere in your Markdown document. I

tend to put them immediately after each paragraph in which they&#8217;re

used, but if you want, you can put them all at the end of your

document, sort of like footnotes.</p>



<p>Here&#8217;s an example of reference links in action:</p>



<pre><code>I get 10 times more traffic from [Google] [1] than from

[Yahoo] [2] or [MSN] [3].



  [1]: http://google.com/        "Google"

  [2]: http://search.yahoo.com/  "Yahoo Search"

  [3]: http://search.msn.com/    "MSN Search"

</code></pre>



<p>Using the implicit link name shortcut, you could instead write:</p>



<pre><code>I get 10 times more traffic from [Google][] than from

[Yahoo][] or [MSN][].



  [google]: http://google.com/        "Google"

  [yahoo]:  http://search.yahoo.com/  "Yahoo Search"

  [msn]:    http://search.msn.com/    "MSN Search"

</code></pre>



<p>Both of the above examples will produce the following HTML output:</p>



<pre><code>&lt;p&gt;I get 10 times more traffic from &lt;a href="http://google.com/"

title="Google"&gt;Google&lt;/a&gt; than from

&lt;a href="http://search.yahoo.com/" title="Yahoo Search"&gt;Yahoo&lt;/a&gt;

or &lt;a href="http://search.msn.com/" title="MSN Search"&gt;MSN&lt;/a&gt;.&lt;/p&gt;

</code></pre>



<p>For comparison, here is the same paragraph written using

Markdown&#8217;s inline link style:</p>



<pre><code>I get 10 times more traffic from [Google](http://google.com/ "Google")

than from [Yahoo](http://search.yahoo.com/ "Yahoo Search") or

[MSN](http://search.msn.com/ "MSN Search").

</code></pre>



<p>The point of reference-style links is not that they&#8217;re easier to

write. The point is that with reference-style links, your document

source is vastly more readable. Compare the above examples: using

reference-style links, the paragraph itself is only 81 characters

long; with inline-style links, it&#8217;s 176 characters; and as raw HTML,

it&#8217;s 234 characters. In the raw HTML, there&#8217;s more markup than there

is text.</p>



<p>With Markdown&#8217;s reference-style links, a source document much more

closely resembles the final output, as rendered in a browser. By

allowing you to move the markup-related metadata out of the paragraph,

you can add links without interrupting the narrative flow of your

prose.</p>



<h3 id="em">Emphasis</h3>



<p>Markdown treats asterisks (<code>*</code>) and underscores (<code>_</code>) as indicators of

emphasis. Text wrapped with one <code>*</code> or <code>_</code> will be wrapped with an

HTML <code>&lt;em&gt;</code> tag; double <code>*</code>&#8217;s or <code>_</code>&#8217;s will be wrapped with an HTML

<code>&lt;strong&gt;</code> tag. E.g., this input:</p>



<pre><code>*single asterisks*



_single underscores_



**double asterisks**



__double underscores__

</code></pre>



<p>will produce:</p>



<pre><code>&lt;em&gt;single asterisks&lt;/em&gt;



&lt;em&gt;single underscores&lt;/em&gt;



&lt;strong&gt;double asterisks&lt;/strong&gt;



&lt;strong&gt;double underscores&lt;/strong&gt;

</code></pre>



<p>You can use whichever style you prefer; the lone restriction is that

the same character must be used to open and close an emphasis span.</p>



<p>Emphasis can be used in the middle of a word:</p>



<pre><code>un*fucking*believable

</code></pre>



<p>But if you surround an <code>*</code> or <code>_</code> with spaces, it&#8217;ll be treated as a

literal asterisk or underscore.</p>



<p>To produce a literal asterisk or underscore at a position where it

would otherwise be used as an emphasis delimiter, you can backslash

escape it:</p>



<pre><code>\*this text is surrounded by literal asterisks\*

</code></pre>



<h3 id="code">Code</h3>



<p>To indicate a span of code, wrap it with backtick quotes (<code>`</code>).

Unlike a pre-formatted code block, a code span indicates code within a

normal paragraph. For example:</p>



<pre><code>Use the `printf()` function.

</code></pre>



<p>will produce:</p>



<pre><code>&lt;p&gt;Use the &lt;code&gt;printf()&lt;/code&gt; function.&lt;/p&gt;

</code></pre>



<p>To include a literal backtick character within a code span, you can

backslash escape it:</p>



<pre><code>`There is a literal backtick (\`) here.`

</code></pre>



<p>Or, if you prefer, you can use multiple backticks as the opening and

closing delimiters:</p>



<pre><code>``There is a literal backtick (`) here.``

</code></pre>



<p>Both of the previous two examples will produce this:</p>



<pre><code>&lt;p&gt;&lt;code&gt;There is a literal backtick (`) here.&lt;/code&gt;&lt;/p&gt;

</code></pre>



<p>With a code span, ampersands and angle brackets are encoded as HTML

entities automatically, which makes it easy to include example HTML

tags. Markdown will turn this:</p>



<pre><code>Please don't use any `&lt;blink&gt;` tags.

</code></pre>



<p>into:</p>



<pre><code>&lt;p&gt;Please don't use any &lt;code&gt;&amp;lt;blink&amp;gt;&lt;/code&gt; tags.&lt;/p&gt;

</code></pre>



<p>You can write this:</p>



<pre><code>`&amp;#8212;` is the decimal-encoded equivalent of `&amp;mdash;`.

</code></pre>



<p>to produce:</p>



<pre><code>&lt;p&gt;&lt;code&gt;&amp;amp;#8212;&lt;/code&gt; is the decimal-encoded

equivalent of &lt;code&gt;&amp;amp;mdash;&lt;/code&gt;.&lt;/p&gt;

</code></pre>



<h3 id="img">Images</h3>



<p>Admittedly, it&#8217;s fairly difficult to devise a &#8220;natural&#8221; syntax for

placing images into a plain text document format.</p>



<p>Markdown uses an image syntax that is intended to resemble the syntax

for links, allowing for two styles: <em>inline</em> and <em>reference</em>.</p>



<p>Inline image syntax looks like this:</p>



<pre><code>![Alt text](/path/to/img.jpg)



![Alt text](/path/to/img.jpg "Optional title")

</code></pre>



<p>That is:</p>



<ul>

<li>An exclamation mark: <code>!</code>;</li>

<li>followed by a set of square brackets, containing the <code>alt</code>

attribute text for the image;</li>

<li>followed by a set of parentheses, containing the URL or path to

the image, and an optional <code>title</code> attribute enclosed in double

or single quotes.</li>

</ul>



<p>Reference-style image syntax looks like this:</p>



<pre><code>![Alt text][id]

</code></pre>



<p>Where &#8220;id&#8221; is the name of a defined image reference. Image references

are defined using syntax identical to link references:</p>



<pre><code>[id]: url/to/image  "Optional title attribute"

</code></pre>



<p>As of this writing, Markdown has no syntax for specifying the

dimensions of an image; if this is important to you, you can simply

use regular HTML <code>&lt;img&gt;</code> tags.</p>



<hr />



<h2 id="misc">Miscellaneous</h2>



<h3 id="autolink">Automatic Links</h3>



<p>Markdown supports a shortcut style for creating &#8220;automatic&#8221; links for URLs and email addresses: simply surround the URL or email address with angle brackets. What this means is that if you want to show the actual text of a URL or email address, and also have it be a clickable link, you can do this:</p>



<pre><code>&lt;http://example.com/&gt;

</code></pre>



<p>Markdown will turn this into:</p>



<pre><code>&lt;a href="http://example.com/"&gt;http://example.com/&lt;/a&gt;

</code></pre>



<p>Automatic links for email addresses work similarly, except that

Markdown will also perform a bit of randomized decimal and hex

entity-encoding to help obscure your address from address-harvesting

spambots. For example, Markdown will turn this:</p>



<pre><code>&lt;address@example.com&gt;

</code></pre>



<p>into something like this:</p>



<pre><code>&lt;a href="&amp;#x6D;&amp;#x61;i&amp;#x6C;&amp;#x74;&amp;#x6F;:&amp;#x61;&amp;#x64;&amp;#x64;&amp;#x72;&amp;#x65;

&amp;#115;&amp;#115;&amp;#64;&amp;#101;&amp;#120;&amp;#x61;&amp;#109;&amp;#x70;&amp;#x6C;e&amp;#x2E;&amp;#99;&amp;#111;

&amp;#109;"&gt;&amp;#x61;&amp;#x64;&amp;#x64;&amp;#x72;&amp;#x65;&amp;#115;&amp;#115;&amp;#64;&amp;#101;&amp;#120;&amp;#x61;

&amp;#109;&amp;#x70;&amp;#x6C;e&amp;#x2E;&amp;#99;&amp;#111;&amp;#109;&lt;/a&gt;

</code></pre>



<p>which will render in a browser as a clickable link to &#8220;address@example.com&#8221;.</p>



<p>(This sort of entity-encoding trick will indeed fool many, if not

most, address-harvesting bots, but it definitely won&#8217;t fool all of

them. It&#8217;s better than nothing, but an address published in this way

will probably eventually start receiving spam.)</p>



<h3 id="backslash">Backslash Escapes</h3>



<p>Markdown allows you to use backslash escapes to generate literal

characters which would otherwise have special meaning in Markdown&#8217;s

formatting syntax. For example, if you wanted to surround a word with

literal asterisks (instead of an HTML <code>&lt;em&gt;</code> tag), you can backslashes

before the asterisks, like this:</p>



<pre><code>\*literal asterisks\*

</code></pre>



<p>Markdown provides backslash escapes for the following characters:</p>



<pre><code>\   backslash

`   backtick

*   asterisk

_   underscore

{}  curly braces

[]  square brackets

()  parentheses

#   hash mark

.   dot

!   exclamation mark

</code></pre>



</div> <!-- article -->