mirror of
https://github.com/moodle/moodle.git
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948 lines
31 KiB
HTML
948 lines
31 KiB
HTML
<html>
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<head>
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<title>Markdown</title>
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</head>
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<body>
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<p align="center"><b>Markdown-Formatierung zur
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Erstellung von Web-Seiten</b></p>
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<p>Markdown Formatierungen ermöglichen es, Texte einfach zu
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formatieren ohne dabei auf einen Editor zurückzugreifen. Die
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Formatierungen erfolgen ähnlich wie in Wiki-Texten durch
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Auszeichnungen der Texte.</p>
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<p>(Dieser Text ist eine Kopie von <a target="_blank" href=
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"http://daringfireball.net/projects/markdown/syntax">der Orginal
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Markdown-Syntax Seite</a>)</p>
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<hr>
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<div id="Main">
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<div class="article">
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<ul>
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<li><a href="#overview">Overview</a>
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<ul>
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<li><a href="#philosophy">Philosophy</a></li>
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<li><a href="#html">Inline HTML</a></li>
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<li><a href="#autoescape">Automatic Escaping for Special
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Characters</a></li>
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</ul>
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</li>
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<li><a href="#block">Block Elements</a>
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<ul>
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<li><a href="#p">Paragraphs and Line Breaks</a></li>
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<li><a href="#header">Headers</a></li>
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<li><a href="#blockquote">Blockquotes</a></li>
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<li><a href="#list">Lists</a></li>
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<li><a href="#precode">Code Blocks</a></li>
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<li><a href="#hr">Horizontal Rules</a></li>
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</ul>
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</li>
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<li><a href="#span">Span Elements</a>
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<ul>
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<li><a href="#link">Links</a></li>
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<li><a href="#em">Emphasis</a></li>
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<li><a href="#code">Code</a></li>
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<li><a href="#img">Images</a></li>
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</ul>
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</li>
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<li><a href="#misc">Miscellaneous</a>
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<ul>
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<li><a href="#backslash">Backslash Escapes</a></li>
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<li><a href="#autolink">Automatic Links</a></li>
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</ul>
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</li>
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</ul>
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<hr>
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<h2 id="overview">Overview</h2>
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<h3 id="philosophy">Philosophy</h3>
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<p>Markdown is intended to be as easy-to-read and easy-to-write
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as is feasible.</p>
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<p>Readability, however, is emphasized above all else. A
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Markdown-formatted document should be publishable as-is, as plain
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text, without looking like it’s been marked up with tags or
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formatting instructions. While Markdown’s syntax has been
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influenced by several existing text-to-HTML filters —
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including <a href=
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"http://docutils.sourceforge.net/mirror/setext.html">Setext</a>,
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<a href="http://www.aaronsw.com/2002/atx/">atx</a>, <a href=
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"http://textism.com/tools/textile/">Textile</a>, <a href=
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"http://docutils.sourceforge.net/rst.html">reStructuredText</a>,
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<a href=
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"http://www.triptico.com/software/grutatxt.html">Grutatext</a>,
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and <a href="http://ettext.taint.org/doc/">EtText</a> — the
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single biggest source of inspiration for Markdown’s syntax
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is the format of plain text email.</p>
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<p>To this end, Markdown’s syntax is comprised entirely of
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punctuation characters, which punctuation characters have been
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carefully chosen so as to look like what they mean. E.g.,
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asterisks around a word actually look like *emphasis*. Markdown
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lists look like, well, lists. Even blockquotes look like quoted
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passages of text, assuming you’ve ever used email.</p>
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<h3 id="html">Inline HTML</h3>
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<p>Markdown’s syntax is intended for one purpose: to be
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used as a format for <em>writing</em> for the web.</p>
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<p>Markdown is not a replacement for HTML, or even close to it.
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Its syntax is very small, corresponding only to a very small
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subset of HTML tags. The idea is <em>not</em> to create a syntax
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that makes it easier to insert HTML tags. In my opinion, HTML
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tags are already easy to insert. The idea for Markdown is to make
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it easy to read, write, and edit prose. HTML is a
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<em>publishing</em> format; Markdown is a <em>writing</em>
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format. Thus, Markdown’s formatting syntax only addresses
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issues that can be conveyed in plain text.</p>
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<p>For any markup that is not covered by Markdown’s syntax,
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you simply use HTML itself. There’s no need to preface it
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or delimit it to indicate that you’re switching from
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Markdown to HTML; you just use the tags.</p>
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<p>The only restrictions are that block-level HTML elements
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— e.g. <code><div></code>,
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<code><table></code>, <code><pre></code>,
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<code><p></code>, etc. — must be separated from
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surrounding content by blank lines, and the start and end tags of
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the block should not be indented with tabs or spaces. Markdown is
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smart enough not to add extra (unwanted) <code><p></code>
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tags around HTML block-level tags.</p>
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<p>For example, to add an HTML table to a Markdown article:</p>
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<pre>
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<code>This is a regular paragraph.
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<table>
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<tr>
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<td>Foo</td>
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</tr>
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</table>
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This is another regular paragraph.
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</code>
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</pre>
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<p>Note that Markdown formatting syntax is not processed within
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block-level HTML tags. E.g., you can’t use Markdown-style
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<code>*emphasis*</code> inside an HTML block.</p>
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<p>Span-level HTML tags — e.g. <code><span></code>,
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<code><cite></code>, or <code><del></code> —
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can be used anywhere in a Markdown paragraph, list item, or
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header. If you want, you can even use HTML tags instead of
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Markdown formatting; e.g. if you’d prefer to use HTML
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<code><a></code> or <code><img></code> tags instead
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of Markdown’s link or image syntax, go right ahead.</p>
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<p>Unlike block-level HTML tags, Markdown syntax <em>is</em>
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processed within span-level tags.</p>
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<h3 id="autoescape">Automatic Escaping for Special
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Characters</h3>
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<p>In HTML, there are two characters that demand special
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treatment: <code><</code> and <code>&</code>. Left angle
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brackets are used to start tags; ampersands are used to denote
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HTML entities. If you want to use them as literal characters, you
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must escape them as entities, e.g. <code>&lt;</code>, and
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<code>&amp;</code>.</p>
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<p>Ampersands in particular are bedeviling for web writers. If
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you want to write about ‘AT&T’, you need to write
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‘<code>AT&amp;T</code>’. You even need to escape
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ampersands within URLs. Thus, if you want to link to:</p>
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<pre>
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<code>http://images.google.com/images?num=30&q=larry+bird
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</code>
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</pre>
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<p>you need to encode the URL as:</p>
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<pre>
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<code>http://images.google.com/images?num=30&amp;q=larry+bird
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</code>
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</pre>
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<p>in your anchor tag <code>href</code> attribute. Needless to
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say, this is easy to forget, and is probably the single most
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common source of HTML validation errors in otherwise
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well-marked-up web sites.</p>
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<p>Markdown allows you to use these characters naturally, taking
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care of all the necessary escaping for you. If you use an
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ampersand as part of an HTML entity, it remains unchanged;
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otherwise it will be translated into <code>&amp;</code>.</p>
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<p>So, if you want to include a copyright symbol in your article,
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you can write:</p>
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<pre>
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<code>&copy;
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</code>
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</pre>
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<p>and Markdown will leave it alone. But if you write:</p>
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<pre>
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<code>AT&T
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</code>
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</pre>
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<p>Markdown will translate it to:</p>
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<pre>
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<code>AT&amp;T
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</code>
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</pre>
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<p>Similarly, because Markdown supports <a href="#html">inline
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HTML</a>, if you use angle brackets as delimiters for HTML tags,
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Markdown will treat them as such. But if you write:</p>
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<pre>
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<code>4 < 5
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</code>
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</pre>
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<p>Markdown will translate it to:</p>
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<pre>
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<code>4 &lt; 5
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</code>
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</pre>
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<p>However, inside Markdown code spans and blocks, angle brackets
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and ampersands are <em>always</em> encoded automatically. This
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makes it easy to use Markdown to write about HTML code. (As
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opposed to raw HTML, which is a terrible format for writing about
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HTML syntax, because every single <code><</code> and
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<code>&</code> in your example code needs to be escaped.)</p>
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<hr>
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<h2 id="block">Block Elements</h2>
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<h3 id="p">Paragraphs and Line Breaks</h3>
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<p>A paragraph is simply one or more consecutive lines of text,
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separated by one or more blank lines. (A blank line is any line
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that looks like a blank line — a line containing nothing
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but spaces or tabs is considered blank.) Normal paragraphs should
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not be intended with spaces or tabs.</p>
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<p>The implication of the “one or more consecutive lines of
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text” rule is that Markdown supports
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“hard-wrapped” text paragraphs. This differs
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significantly from most other text-to-HTML formatters (including
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Movable Type’s “Convert Line Breaks” option)
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which translate every line break character in a paragraph into a
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<code><br /></code> tag.</p>
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<p>When you <em>do</em> want to insert a <code><br
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/></code> break tag using Markdown, you end a line with two or
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more spaces, then type return.</p>
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<p>Yes, this takes a tad more effort to create a <code><br
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/></code>, but a simplistic “every line break is a
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<code><br /></code>” rule wouldn’t work for
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Markdown. Markdown’s email-style <a href=
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"#blockquote">blockquoting</a> and multi-paragraph <a href=
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"#list">list items</a> work best — and look better —
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when you format them with hard breaks.</p>
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<h3 id="header">Headers</h3>
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<p>Markdown supports two styles of headers, <a href=
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"http://docutils.sourceforge.net/mirror/setext.html">Setext</a>
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and <a href="http://www.aaronsw.com/2002/atx/">atx</a>.</p>
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<p>Setext-style headers are “underlined” using equal
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signs (for first-level headers) and dashes (for second-level
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headers). For example:</p>
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<pre>
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<code>This is an H1
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=============
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This is an H2
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-------------
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</code>
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</pre>
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<p>Any number of underlining <code>=</code>’s or
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<code>-</code>’s will work.</p>
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<p>Atx-style headers use 1-6 hash characters at the start of the
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line, corresponding to header levels 1-6. For example:</p>
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<pre>
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<code># This is an H1
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## This is an H2
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###### This is an H6
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</code>
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</pre>
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<p>Optionally, you may “close” atx-style headers.
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This is purely cosmetic — you can use this if you think it
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looks better. The closing hashes don’t even need to match
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the number of hashes used to open the header. (The number of
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opening hashes determines the header level.) :</p>
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<pre>
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<code># This is an H1 #
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## This is an H2 ##
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### This is an H3 ######
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</code>
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</pre>
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<h3 id="blockquote">Blockquotes</h3>
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<p>Markdown uses email-style <code>></code> characters for
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blockquoting. If you’re familiar with quoting passages of
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text in an email message, then you know how to create a
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blockquote in Markdown. It looks best if you hard wrap the text
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and put a <code>></code> before every line:</p>
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<pre>
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<code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet,
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> consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus.
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> Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus.
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>
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> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse
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> id sem consectetuer libero luctus adipiscing.
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</code>
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</pre>
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<p>Markdown allows you to be lazy and only put the
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<code>></code> before the first line of a hard-wrapped
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paragraph:</p>
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<pre>
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<code>> This is a blockquote with two paragraphs. Lorem ipsum dolor sit amet,
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consectetuer adipiscing elit. Aliquam hendrerit mi posuere lectus.
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Vestibulum enim wisi, viverra nec, fringilla in, laoreet vitae, risus.
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> Donec sit amet nisl. Aliquam semper ipsum sit amet velit. Suspendisse
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id sem consectetuer libero luctus adipiscing.
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</code>
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</pre>
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<p>Blockquotes can be nested (i.e. a blockquote-in-a-blockquote)
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by adding additional levels of <code>></code>:</p>
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<pre>
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<code>> This is the first level of quoting.
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>
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> > This is nested blockquote.
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>
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> Back to the first level.
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</code>
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</pre>
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<p>Blockquotes can contain other Markdown elements, including
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headers, lists, and code blocks:</p>
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<pre>
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<code>> ## This is a header.
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>
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> 1. This is the first list item.
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> 2. This is the second list item.
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>
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> Here's some example code:
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>
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> return shell_exec("echo $input | $markdown_script");
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</code>
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</pre>
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<p>Any decent text editor should make email-style quoting easy.
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For example, with BBEdit, you can make a selection and choose
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Increase Quote Level from the Text menu.</p>
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<h3 id="list">Lists</h3>
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<p>Markdown supports ordered (numbered) and unordered (bulleted)
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lists.</p>
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<p>Unordered lists use asterisks, pluses, and hyphens —
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interchangably — as list markers:</p>
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<pre>
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<code>* Red
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* Green
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* Blue
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</code>
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</pre>
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<p>is equivalent to:</p>
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<pre>
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<code>+ Red
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+ Green
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+ Blue
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</code>
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</pre>
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<p>and:</p>
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<pre>
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<code>- Red
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- Green
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- Blue
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</code>
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</pre>
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<p>Ordered lists use numbers followed by periods:</p>
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<pre>
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<code>1. Bird
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2. McHale
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3. Parish
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</code>
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</pre>
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<p>It’s important to note that the actual numbers you use
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to mark the list have no effect on the HTML output Markdown
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produces. The HTML Markdown produces from the above list is:</p>
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<pre>
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<code><ol>
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<li>Bird</li>
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<li>McHale</li>
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<li>Parish</li>
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</ol>
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</code>
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</pre>
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<p>If you instead wrote the list in Markdown like this:</p>
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<pre>
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<code>1. Bird
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1. McHale
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1. Parish
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</code>
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</pre>
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<p>or even:</p>
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<pre>
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<code>3. Bird
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1. McHale
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8. Parish
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</code>
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</pre>
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<p>you’d get the exact same HTML output. The point is, if
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you want to, you can use ordinal numbers in your ordered Markdown
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lists, so that the numbers in your source match the numbers in
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your published HTML. But if you want to be lazy, you don’t
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have to.</p>
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<p>If you do use lazy list numbering, however, you should still
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start the list with the number 1. At some point in the future,
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Markdown may support starting ordered lists at an arbitrary
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number.</p>
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<p>List markers typically start at the left margin, but may be
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indented by up to three spaces. List markers must be followed by
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one or more spaces or a tab.</p>
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<p>To make lists look nice, you can wrap items with hanging
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indents:</p>
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<pre>
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<code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
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Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi,
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viverra nec, fringilla in, laoreet vitae, risus.
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* Donec sit amet nisl. Aliquam semper ipsum sit amet velit.
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Suspendisse id sem consectetuer libero luctus adipiscing.
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</code>
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</pre>
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<p>But if you want to be lazy, you don’t have to:</p>
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<pre>
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<code>* Lorem ipsum dolor sit amet, consectetuer adipiscing elit.
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Aliquam hendrerit mi posuere lectus. Vestibulum enim wisi,
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viverra nec, fringilla in, laoreet vitae, risus.
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* Donec sit amet nisl. Aliquam semper ipsum sit amet velit.
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Suspendisse id sem consectetuer libero luctus adipiscing.
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</code>
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</pre>
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<p>If list items are separated by blank lines, Markdown will wrap
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the items in <code><p></code> tags in the HTML output. For
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example, this input:</p>
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<pre>
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<code>* Bird
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* Magic
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</code>
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</pre>
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<p>will turn into:</p>
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<pre>
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<code><ul>
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<li>Bird</li>
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<li>Magic</li>
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</ul>
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</code>
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</pre>
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<p>But this:</p>
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<pre>
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<code>* Bird
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* Magic
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</code>
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</pre>
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<p>will turn into:</p>
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<pre>
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<code><ul>
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<li><p>Bird</p></li>
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<li><p>Magic</p></li>
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</ul>
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</code>
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</pre>
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<p>List items may consist of multiple paragraphs. Each subsequent
|
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paragraph in a list item must be intended by either 4 spaces or
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one tab:</p>
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<pre>
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<code>1. This is a list item with two paragraphs. Lorem ipsum dolor
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sit amet, consectetuer adipiscing elit. Aliquam hendrerit
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mi posuere lectus.
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Vestibulum enim wisi, viverra nec, fringilla in, laoreet
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vitae, risus. Donec sit amet nisl. Aliquam semper ipsum
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sit amet velit.
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2. Suspendisse id sem consectetuer libero luctus adipiscing.
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</code>
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</pre>
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<p>It looks nice if you indent every line of the subsequent
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paragraphs, but here again, Markdown will allow you to be
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lazy:</p>
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<pre>
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<code>* This is a list item with two paragraphs.
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This is the second paragraph in the list item. You're
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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’s
|
|
<code>></code> delimiters need to be indented:</p>
|
|
<pre>
|
|
<code>* A list item with a blockquote:
|
|
|
|
> This is a blockquote
|
|
> 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> — 8 spaces or two tabs:</p>
|
|
<pre>
|
|
<code>* A list item with a code block:
|
|
|
|
<code goes here>
|
|
</code>
|
|
</pre>
|
|
<p>It’s worth noting that it’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><pre></code> and
|
|
<code><code></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><p>This is a normal paragraph:</p>
|
|
|
|
<pre><code>This is a code block.
|
|
</code></pre>
|
|
</code>
|
|
</pre>
|
|
<p>One level of indentation — 4 spaces or 1 tab — 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><p>Here is an example of AppleScript:</p>
|
|
|
|
<pre><code>tell application "Foo"
|
|
beep
|
|
end tell
|
|
</code></pre>
|
|
</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>&</code>) and angle
|
|
brackets (<code><</code> and <code>></code>) are
|
|
automatically converted into HTML entities. This makes it very
|
|
easy to include example HTML source code using Markdown —
|
|
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> <div class="footer">
|
|
&copy; 2004 Foo Corporation
|
|
</div>
|
|
</code>
|
|
</pre>
|
|
<p>will turn into:</p>
|
|
<pre>
|
|
<code><pre><code>&lt;div class="footer"&gt;
|
|
&amp;copy; 2004 Foo Corporation
|
|
&lt;/div&gt;
|
|
</code></pre>
|
|
</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’s also easy to use Markdown to write about
|
|
Markdown’s own syntax.</p>
|
|
<h3 id="hr">Horizontal Rules</h3>
|
|
<p>You can produce a horizontal rule tag (<code><hr
|
|
/></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’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><p>This is <a href="http://example.com/" title="Title">
|
|
an example</a> inline link.</p>
|
|
|
|
<p><a href="http://example.net/">This link</a> has no
|
|
title attribute.</p>
|
|
</code>
|
|
</pre>
|
|
<p>If you’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]: <http://example.com/> "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 — 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 —
|
|
e.g., to link the word “Google” 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’re used, but if you want, you can put them all
|
|
at the end of your document, sort of like footnotes.</p>
|
|
<p>Here’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><p>I get 10 times more traffic from <a href="http://google.com/"
|
|
title="Google">Google</a> than from
|
|
<a href="http://search.yahoo.com/" title="Yahoo Search">Yahoo</a>
|
|
or <a href="http://search.msn.com/" title="MSN Search">MSN</a>.</p>
|
|
</code>
|
|
</pre>
|
|
<p>For comparison, here is the same paragraph written using
|
|
Markdown’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’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’s 176
|
|
characters; and as raw HTML, it’s 234 characters. In the
|
|
raw HTML, there’s more markup than there is text.</p>
|
|
<p>With Markdown’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><em></code> tag; double <code>*</code>’s or
|
|
<code>_</code>’s will be wrapped with an HTML
|
|
<code><strong></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><em>single asterisks</em>
|
|
|
|
<em>single underscores</em>
|
|
|
|
<strong>double asterisks</strong>
|
|
|
|
<strong>double underscores</strong>
|
|
</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’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><p>Use the <code>printf()</code> function.</p>
|
|
</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><p><code>There is a literal backtick (`) here.</code></p>
|
|
</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 `<blink>` tags.
|
|
</code>
|
|
</pre>
|
|
<p>into:</p>
|
|
<pre>
|
|
<code><p>Please don't use any <code>&lt;blink&gt;</code> tags.</p>
|
|
</code>
|
|
</pre>
|
|
<p>You can write this:</p>
|
|
<pre>
|
|
<code>`&#8212;` is the decimal-encoded equivalent of `&mdash;`.
|
|
</code>
|
|
</pre>
|
|
<p>to produce:</p>
|
|
<pre>
|
|
<code><p><code>&amp;#8212;</code> is the decimal-encoded
|
|
equivalent of <code>&amp;mdash;</code>.</p>
|
|
</code>
|
|
</pre>
|
|
<h3 id="img">Images</h3>
|
|
<p>Admittedly, it’s fairly difficult to devise a
|
|
“natural” 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>
|
|
|
|
|
|
</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 “id” 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><img></code> tags.</p>
|
|
<hr>
|
|
<h2 id="misc">Miscellaneous</h2>
|
|
<h3 id="autolink">Automatic Links</h3>
|
|
<p>Markdown supports a shortcut style for creating
|
|
“automatic” 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><http://example.com/>
|
|
</code>
|
|
</pre>
|
|
<p>Markdown will turn this into:</p>
|
|
<pre>
|
|
<code><a href="http://example.com/">http://example.com/</a>
|
|
</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><address@example.com>
|
|
</code>
|
|
</pre>
|
|
<p>into something like this:</p>
|
|
<pre>
|
|
<code><a href="&#x6D;&#x61;i&#x6C;&#x74;&#x6F;:&#x61;&#x64;&#x64;&#x72;&#x65;
|
|
&#115;&#115;&#64;&#101;&#120;&#x61;&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;
|
|
&#109;">&#x61;&#x64;&#x64;&#x72;&#x65;&#115;&#115;&#64;&#101;&#120;&#x61;
|
|
&#109;&#x70;&#x6C;e&#x2E;&#99;&#111;&#109;</a>
|
|
</code>
|
|
</pre>
|
|
<p>which will render in a browser as a clickable link to
|
|
“address@example.com”.</p>
|
|
<p>(This sort of entity-encoding trick will indeed fool many, if
|
|
not most, address-harvesting bots, but it definitely won’t
|
|
fool all of them. It’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’s formatting syntax. For example, if you wanted to
|
|
surround a word with literal asterisks (instead of an HTML
|
|
<code><em></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
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{} curly braces
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[] square brackets
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() parentheses
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# hash mark
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. dot
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! exclamation mark
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</code>
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</pre></div>
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